WO2025111348A1 - Modular, reconfigurable, and multi-functional robots for rehabilitation - Google Patents

Abstract

A system for providing a reconfigurable robot for physical rehabilitation of a subject includes mechanical modules of different types capable of being assembled into different robot configurations for different physical rehabilitation exercises, the mechanical modules at least one frame module for supporting a structure of the robot configurations; at least one rail module comprising at least one slider, a platform mounted on the at least one slider, and a motor for moving the platform linearly on the at least one slider; at least one leg module including a leg comprising an elongate member and a revolute joint connected to one end of the leg; and at least one handle module for connecting to the rail module or the leg module for allowing a user to move the platform or the leg.

Description

MODULAR, RECONFIGURABLE, AND MULTI-FUNCTIONAL ROBOTS FOR REHABILITATION

PRIORITY CLAIM

This application claims the priority benefit of U.S. Provisional Patent Application Serial No. 63/601 ,025 filed November 20, 2023, the disclosure of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The subject matter described herein relates generally to multifunctional robots for rehabilitation and, in particular, to modular, reconfigurable robots.

BACKGROUND

Upper-limb movement disorders limit patients’ independence in the accomplishment activities of daily living (ADLs), reducing their Quality-of-Life (QoL). Such impairments may be due to cerebrovascular accidents (e.g., stroke), spinal cord injuries (SCIs), cerebral palsy (CP), multiple sclerosis (MP) and musculoskeletal disorders (MSDs). Nowadays, several approaches can be carried out to restore the functionality of the upper extremity such as physical therapy, orthoses, and functional electrical stimulations (FES).

Since the 1990’s, many research groups have started to develop robotic devices for upper limb rehabilitation. The rationale for using robotic systems in rehabilitation field is that such devices can provide accurate, repetitive, high-intensive, task-specific and interactive treatment of the impaired limb increasing training frequency and rehabilitation outcomes. Rehabilitation robots have been extensively tested in clinical trials to evaluate the effectiveness of robot-aided therapy, showing positive outcomes in terms of motor function improvements, especially in the upper extremities. Despite these promising results, the usage of robots in current clinical practice is still limited due to their high mechanical complexity (multiple joints with sophisticated mechanisms and drives) causing them to be large and expensive. Such issues limit robots’ cost-benefit profile, reducing their large- scale usage.

A method to overcome such limitations could be to implement a modular and reconfigurable approach in the design of these systems. Although this kind of approach has been already leveraged/exploited for the design of therapy robots, they are still expensive, not suitable for large scale use, and not suitable for providing different types of therapy. Hence, there is still a pressing need to investigate how the principles of modularity and reconfigurability can be applied to design high-performance, multi-purpose, low-cost and portable therapy robots for clinical settings, community-based settings, and home-based settings.

SUMMARY

The subject matter described herein includes methods for configuring rehabilitation robots that can be applied to design modular and reconfigurable therapy devices able to overcome the limitations of current rehabilitation robots in terms of affordability, usability, functionality and portability.

The subject matter described herein also includes a reconfigurable robot suitable for physical therapy and rehabilitation.

A method for configuring a robot for rehabilitation of a subject includes, in a top-down configuration phase: identifying a plurality of design requirements; selecting a plurality of robotic mechanisms; and performing a configurations analysis using the robotic mechanisms. The method further includes, in a bottom-up configuration phase, identifying a plurality of robot configuration modules based on the configurations analysis; for each robot configuration module, determining a mechatronic structure for the robot configuration module; configuring the robot into a first robot configuration for a first type of rehabilitation therapy; and configuring the robot into a second robot configuration for a second type of rehabilitation therapy.

According to another aspect of the subject matter described herein, identifying the design requirements comprises identifying one or more high- level design requirements and one or more low-level design requirements. According to another aspect of the subject matter described herein, selecting the robotic mechanisms comprises selecting, for each configuration of a plurality of configurations of the robot, a kinematic structure for the configuration, wherein each kinematic structure comprises an open kinematic chain or a closed kinematic chain.

According to another aspect of the subject matter described herein, performing the configurations analysis comprises analyzing, using at least one processor, the kinematics, statics, and dynamics of each of the configurations.

According to another aspect of the subject matter described herein, identifying the robot configuration modules comprises determining a plurality of dimensions for the configurations using the design requirements.

According to another aspect of the subject matter described herein, determining the dimensions comprises determining at least one of: a length of a link or a workspace size.

According to another aspect of the subject matter described herein, determining a mechatronic structure comprises determining at least one of: an actuation system sizing or selection of a mechanical transmission.

According to another aspect of the subject matter described herein, identifying the design requirements comprises analyzing a target population, a type of therapy, and one or more rehabilitation scenarios.

According to another aspect of the subject matter described herein, configuring the robot into a first configuration for a first type of rehabilitation therapy comprises configuring the robot for coupled bilateral therapy, and wherein configuring the robot into a second configuration for a second type of rehabilitation therapy comprises configuring the robot for independent bilateral therapy.

According to another aspect of the subject matter described herein, identifying the robot configuration modules comprises selecting one or more of: a rail module, a leg module, a frame module, and a handle module.

According to another aspect of the subject matter described herein, a system for providing a reconfigurable robot for physical rehabilitation of a subject is provided. The system includes a plurality of mechanical modules of different types capable of being assembled into different robot configurations for different physical rehabilitation exercises. The plurality of mechanical modules includes at least one frame module for supporting a structure of the robot configurations, at least one rail module comprising at least one slider, a platform mounted on the at least one slider, and a motor for moving the platform linearly on the at least one slider, at least one leg module including a leg comprising an elongate member and a revolute joint connected to one end of the leg, at least one handle module for connecting to the rail module or the leg module for allowing a user to move the platform or the leg.

According to another aspect of the subject matter described herein, the at least one rail module, the at least one frame module, and the at least one handle module are connectable to each other to form a prismatic joint (P) robot configuration for one degree of freedom therapies.

According to another aspect of the subject matter described herein, the at least one rail module comprises two rail modules, the at least one handle module comprises two handle modules respectively connectable to the rail modules, and the rail modules are connectable to the at least one frame module to form a prismatic/prismatic (P/P) robot configuration for one degree of freedom therapies to two limbs of a subject.

According to another aspect of the subject matter described herein, the at least one leg module comprises two leg modules, each comprising a leg having a first end connectable to one of the rail modules via a revolute joint of the leg module to form a prismatic, revolute/prismatic, revolute (PR/PR) robot configuration.

According to another aspect of the subject matter described herein, the system comprises a third revolute joint for connecting second ends of the first and second legs together to form a prismatic, revolute, revolute, revolute, prismatic (PRRRP) robot configuration.

According to another aspect of the subject matter described herein, a first end of the leg is connectable to the rail module via the revolute joint and a second end of the leg is coupled to the at least one handle module to form a prismatic, revolute (PR) robot configuration.

According to another aspect of the subject matter described herein, the at least one rail module comprises a belt coupled between the motor and the at least one slider.

According to another aspect of the subject matter described herein, the belt comprises a timing belt.

According to another aspect of the subject matter described herein, the motor comprises a direct current (DC) motor, a quasi-direct drive motor, or any actuator capable of moving the belt and/or the platform.

According to another aspect of the subject matter described herein, the at least one handle module comprises a prismatic (P) handle module for connecting to the platform in P robot configuration, a revolute (R) handle module for connecting to the platform and the revolute joint in a PR robot configuration, and a PRRRP handle module for connecting to the platform, the revolute joint, and two instance of the leg in a PRRRP robot configuration.

The computer systems described herein may be implemented in hardware, software, firmware, or any combination thereof. As such, the terms “function” or “node” as used herein refer to hardware, which may also include software and/or firmware components, for implementing the feature(s) being described. In some exemplary implementations, the subject matter described herein may be implemented using a computer readable medium having stored thereon computer executable instructions that when executed by the processor of a computer control the computer to perform steps. Exemplary computer readable media suitable for implementing the subject matter described herein include non-transitory computer readable media, such as disk memory devices, chip memory devices, programmable logic devices, and application specific integrated circuits. In addition, a computer readable medium that implements the subject matter described herein may be located on a single device or computing platform or may be distributed across multiple devices or computing platforms. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a flow diagram of an example method for configuring a rehabilitation robot;

Figure 2 is a diagram illustrating configurations of a modular robot for different types of rehabilitation;

Figure 3A is a diagram illustrating a rail module of a modular robot;

Figure 3B is a diagram illustrating a leg module of a modular robot;

Figure 3C is a diagram illustrating a frame module of a modular robot; Figure 3D is a diagram illustrating a handle module of a modular robot; Figure 4 is a schematic diagram illustrating different configurations of the modular robot using the rail, leg, frame, and handle modules; and

Figure 5 is a diagram illustrating different configurations of a modular robot and used of the different configurations to perform physical rehabilitation.

DETAILED DESCRIPTION

The subject matter described herein includes methods for designing affordable and multi-functional robots for upper-limb rehabilitation leveraging modular and reconfigurable principles. Such methods allow building robots formed by modules which can be easily integrated with each other forming several mechanical configurations (both closed and open kinematic chains) which can be used to provide multiple upper-limb training movements with variable degrees of freedom (DoFs) and difficulty levels, addressing the therapeutic needs of patients with different residual motor skills. Thanks to their modularity and reconfigurability, such robots can offer several solutions with different costs, adapting the device to users with different economic means. Moreover, they achieve a high level of portability and compactness: their modules can be easily disassembled, assembled, and moved even by non-healthcare workers. Hence, they can be used in several rehabilitation scenarios, such as hospital settings, clinical settings, and home-based settings. In general, they can be used in low-resource rehabilitation settings in urban and rural spaces in high-income countries and low-and-middle income countries.

Figure 1 is a flow diagram of an example method for configuring a rehabilitation robot. The diagram comprises an iterative flowchart divided into two phases: the top-down phase and the bottom-up phase. The top-down phase focuses on the definition of the design requirements of the robot according to the application (e.g., target population, type of therapy) and the analysis of the different configurations of the system (from the more complex to the simpler one). The kinematic and dynamic tools obtained are hence used to define the optimal dimensions of the robot according to the design requirements previously defined. The bottom-up phase, instead, comprises using the output of the top-down phase to design the mechatronic structure of the robot modules. Such modules are then assembled to form the final configurations of the device (from the simpler configuration to the more complex one).

As illustrated in Figure 1 the method comprises the following steps:

• Step 1 : Defining the design requirements of the robot. Such requirements can be obtained considering the following key aspects: a) Target population (e.g., patients with neurological or musculoskeletal disorder); b) Type of therapy (e.g., unilateral or bilateral); c) Rehabilitation scenario (e.g., hospitals, clinics, homebased settings); d) Literature analysis.

The design requirements can be divided into two groups - high-level requirements and low-level requirements. High-level requirements are the general specifications that the robot must meet in order to provide a useful and safe interaction with the patient (qualitative information). Low-level requirements, instead, include the technical specifications of the device (quantitative information). The definition of the design requirements allows the designer to include the patient into the design algorithm (human-centered approach). • Step 2: Selecting the mechanism and kinematic structure (e.g., open and/or closed kinematic chain) of the n configurations of the robot. Such structures can be selected considering the following key points: a) Maximizing the ease with which it is possible to move from one configuration to the others and shift from open kinematic chains to closed ones and vice versa. In this way, the robot can be easily assembled, even by non-healthcare workers; b) Optimizing the possibility of enabling multiple upper-limb trainings with variable DoFs using a single system with a simple mechanical structure; c) Minimizing the numbers of actuators to reduce the costs, the masses, and the overall encumbrance of the device. Such a goal can be achieved by exploiting passive elements (such as brakes, springs) and/or under-actuated solutions.

• Step 3: Analyzing the kinematics, statics and dynamics of the n configurations of the robot from the more complex (configuration 1 ) to the simpler one (configuration /?);

• Step 4: Applying the kinematic and dynamic tools (e.g., manipulability and isotropy ellipsoids, dynamic models) obtained in the previous step are used to define the optimal dimensions (e.g., links length, workspace sizes) of the robot configurations according to the design requirements introduced in Step 1 ;

• Step 5: Dividing the robot into m modules (e.g., actuation module, handle module) and designing their mechatronic structure (e.g., actuation system sizing, selection of the mechanical transmissions) according to the optimal dimensions defined in the previous step and to the low-level design requirements;

• Step 6: After having designed the m modules, the m modules can be assembled in order to obtain the n configurations starting from simple to more complex configurations; and • Step 7: Evaluating the performance of the n configurations of the robot.

The method has been implemented to design a low-cost, modular, and reconfigurable therapy robot for upper-limb rehabilitation: PentaRob. PentaRob is a 1 -2 DoFs robot that includes four modules which can be easily integrated with each other allowing five different configurations. The steps that have been followed to design PentaRob are:

• Step 1 : Defining the design requirements of the robot. Such requirements have been defined considering the following aspects of the application: a) Target population: persons with non-traumatic brain injury, such as those that have had a stroke; b) Type of therapy: shoulder and elbow unilateral/bilateral training movements with variable DoFs; c) Rehabilitation scenarios: both centralized and decentralized settings; d) Literature analysis: existing rehabilitation robots applied to stroke;

Some of the high-level requirements are: i) allow upper-limb (shoulder and elbow) rehabilitation for patients with different residual motor skills; ii) provide high level of usability and portability (small sizes and low masses); Hi) provide isotropic and large forces/torques to the patient. The high-level requirements have been translated in low-level specifications, some of them are: i) provide 1 and 2 DoFs training movements for shoulder and elbow; ii) mass and costs lower than 1 1 kg and 4450 €, respectively; Hi) high level of manipulability and kinematic isotropy within its overall workspace;

• Step 2: Selecting the configurations of PentaRob according to the design requirements. Considering such requirements, five different example configurations (n = 5) have been selected.

Figure 2 illustrates the five different example configurations.

Such configurations are: • P robot configuration 200: includes a 1 -DoF (prismatic (slider) joint 202 - P) and fully actuated linear rail 204 able to move the patient’s arm along a linear trajectory performing reaching tasks. In Figure 2, reference numeral 205 indicates the user’s arm or arms. Such a configuration can provide three types of 1 -DoF unilateral therapies: active/passive/interactive;

• P/P robot configuration 206: includes two parallel P robot configurations 200 linked together through a frame (not shown in Figure 2): Such a configuration can be used to provide two types of 1 - DoF bilateral therapy:

• Coupled bilateral therapy: the robot interacts with both the impaired and healthy arm of the subject. The patient’s impaired arm is moved by the robot using the healthy arm’s motion as reference;

• Independent bilateral therapy: the patient moves the P robots of the P/P configurations independently. Such a therapy mode can be used to measure the performance differences of the user’s arms.

• PR robot configuration 208: includes an under-actuated serial manipulator with 2-DoFs: one linear associated to a prismatic joint (P) 202 and one rotational associated to a revolute joint (R) 210. The manipulator is not fully actuated since only prismatic joint 202 is active while revolute joint 210 is passive. PR robot configuration 208 also includes a leg 211 connected to revolute joint 210. Such a configuration allows the user to perform two types of 2-DoFs unilateral therapies: active and interactive;

• PR/PR robot configuration 212: includes two PR robot configurations 208 attached together through a frame (not shown in Figure 2). Such a configuration can provide the same types of bilateral therapies described for P/P robot configuration 206 but using 2-DoFs;

• PRRRP robot configuration 214: a fully actuated 2-DoFs parallel manipulator able to provide planar training movements. PRRP robot configuration 214 comprises a closed kinematic chain including two active prismatic joints (PP) 202 and two links or legs 211 connected through three passive revolute joints (RRR) 216. Considering the type of assistance, the PRRRP configuration can provide three types of 2-DoFs unilateral training modes: active/passive and interactive.

The configurations just described have been selected from among the typical kinematic and mechanic structure of robot manipulators (e.g., SCARA, Cartesian) for three main reasons:

1. The ease with which it is possible to switch from closed kinematic chains (PRRRP) to open kinematic chains (P, PR) and vice versa. Starting, for example, from PRRRP robot configuration 214, it is possible to reconfigured the robot to PR/PR robot configuration 212 simply by separating legs 211 of the robot. Similarly, by removing legs 211 from PR/PR robot configuration 212, it is possible to obtain P/P robot configuration 206. The same process can be performed in reverse starting from P/P robot configuration 206 to obtain PRRRP configuration 214;

2. The possibility of enabling multiple (up to 12) upper-limb (shoulder and elbow) training movements with variable DoFs (e.g., as shown in Figure 2). In this way, the robot can fulfill the therapy needs of patients with different residual motor skills;

3. The possibility of adapting the robot to users with different economic means and therapeutic needs. Since the different configurations can be used either as standalone devices (e.g., P and PR robot configurations 200 and 208) or as parts of a unique devices (P/P robot configuration 206, PR/PR robot configuration 212 and PRRRP robot configuration 214), a user can decide to acquire either a specific configuration or the overall device according to its economic budget and needs; • Step 3: Analyzing the kinematic and dynamic features of the five configurations of the robot starting from the more complex configuration (PRRRP robot configuration 214) to the simpler one (P robot configuration 200);

• Step 4: The kinematic and dynamic tools obtained in the previous step have been used to define an optimal design algorithm that has been implemented to select the best dimensions of the robot in terms of kinematic manipulability and portability;

• Step 5: Dividing the PentaRob configurations into different mechanical modules and designing their mechatronic structure. Considering the configurations illustrated in Figure 2, four modules (m = 4) have been selected and designed. Figures 3A - 3D illustrate the four example mechanical modules:

• Rail module 300 (Figure 3A): includes linear rails 302 (prismatic joint-P) actuated by a DC motor 304 through a timing belt 306 linear transmission. In an alternate example, belt 306 and/or platform 304 can be moved using a quasi-direct drive motor, or any actuator capable of moving belt 306 and/or platform 308. Rail module 300 includes a platform 308 that is fixedly attached to timing belt 306 and slidably coupled to rails 302;

• Leg module 310 (Figure 3B): includes a link 312 connected to a passive revolute joint (R) 314. In one example, revolute joint 314 comprises a magnetic particle brake which is used to dynamically hold the rotation of revolute joint 314 around the axis of revolute joint 314;

• Frame modules 316A and 316B : provide the frame of the robot holding up the mechanical structure of the device. Two types of frame modules have been designed: small fame module 316A and large frame module 316B illustrated in Figure 3C;

• Handle modules 318A, 318B, and 318C: since the different configurations of the robot present a particular end effector-robot interface, three types of handle modules have been designed: P-handle module 318A, PR-handle module 318B and PRRRP-handle module 318C. Handle modules 318A, 318B, and 318C can be positioned to ride above or below the distal end (i.e., the end opposite revolute joint 314) of leg module 310;

• Step 6: The four modules just described can assembled to form the five configurations of PentaRob. Such configurations have been obtained implementing a Bottom-Up approach (for instance, as shown in Figure 4) which includes, firstly assembling the simpler configuration of the robot (P) and then, by gradually adding some modules, the more complex one (PRRRP). More particularly, Figure 4 illustrates P robot configuration 200 formed by mounting rail module 300 on small base module 316A and attaching P- handle module 318A to platform 308. Similarly, P/P robot configuration 206 can be created by mounting two P robot configurations 200 formed using rail modules 300 and P-handle modules 318A to large frame module 316B. PR robot configuration 208 can be created by connecting rail module 300 to small base module 316A, mounting leg module 310 on platform 308 of rail module 300 and mounting R-handle module 318B to the distal end of link 312. PR/PR robot configuration 212 can be created by mounting two PR robot configurations 208 to large frame module 316B. PRRRP robot configuration 214 can be created from PR/PR robot configuration 212 by connecting the distal ends of links 312 together and replacing R-handle modules 318B with a single PRRRP handle module 318C. • Step 7: Evaluating the final performance of PentaRob comparing them with the desired requirements and with similar devices described in the literature. Such comparison shows that the implementation of the modular and reconfigurable principles in the PentaRob design allows development of a robot characterized by the following advantages:

• PentaRob can enable up to 12 upper-limb training movements by using five configurations with a simple mechanical structure and few DoFs. Implementing such a simple mechanical structure the overall cost of the robot can be reduced;

• PentaRob is highly portable and compact;

• PentaRob is suitable both for centralized (hospitals, clinics) and decentralized usage (home-based setting);

• PentaRob can fulfill clinics, hospitals and individual users with different economic requirements and therapeutic needs.

Figure 5 shows the five configurations of PentaRob, including PRRRP robot configuration 214, PR/PR robot configuration 212, PR robot configuration 208, P robot configuration 200, and P/P robot configuration 206. Figure 5 also illustrates the use of robot configurations 200, 206, 208, 212, and 214 to perform upper limb physical rehabilitation activities. For example, a user 500 can exercise a single arm by grasping P-handle module 318A and sliding platform 308 linearly on rails 302. User 500 can exercise both arms simultaneously using P/P robot configuration 206. User 500 can exercise the wrist, elbow, and shoulder joints of one arm using PR robot configuration 208. User 500 can exercise the wrist, elbow, and shoulder joints of both arms using PR/PR robot configuration 212. User 500 can exercise the wrist, elbow, and shoulder joints of both arms in a stirring-like motion by grasping PRRP handle module 318C with one or both hands and rotating each link 312 about the axis of its respective revolute joint 314 while sliding each leg module 310 linearly on the slider joints of rail modules 300. In conclusion, the modular and reconfigurable approach implemented in the design of PentaRob allows building a robot that, thanks to its unique features, can overcome the limitations of current therapy devices, bridging the gap between the state-of-the-art related to rehabilitation robots and their real-world application.

Although specific examples and features have been described above, these examples and features are not intended to limit the scope of the present disclosure, even where only a single example is described with respect to a particular feature. Examples of features provided in the disclosure are intended to be illustrative rather than restrictive unless stated otherwise. The above description is intended to cover such alternatives, modifications, and equivalents as would be apparent to a person skilled in the art having the benefit of this disclosure.

The scope of the present disclosure includes any feature or combination of features disclosed in this specification (either explicitly or implicitly), or any generalization of features disclosed, whether or not such features or generalizations mitigate any or all of the problems described in this specification. Accordingly, new claims may be formulated during prosecution of this application (or an application claiming priority to this application) to any such combination of features. In particular, with reference to the appended claims, features from dependent claims may be combined with those of the independent claims and features from respective independent claims may be combined in any appropriate manner and not merely in the specific combinations enumerated in the appended claims.

Claims

CLAIMS What is claimed is:

1 . A method for configuring a robot for rehabilitation of a subject, the method comprising: in a top-down configuration phase: identifying a plurality of design requirements; selecting a plurality of robotic mechanisms; and performing a configurations analysis using the robotic mechanisms; in a bottom-up configuration phase: identifying a plurality of robot configuration modules based on the configurations analysis; for each robot configuration module, determining a mechatronic structure for the robot configuration module; configuring the robot into a first robot configuration for a first type of rehabilitation therapy; and configuring the robot into a second robot configuration for a second type of rehabilitation therapy.

2. The method of claim 1 , wherein identifying the design requirements comprises identifying one or more high-level design requirements and one or more low-level design requirements.

3. The method of claim 1 , wherein selecting the robotic mechanisms comprises selecting, for each configuration of a plurality of configurations of the robot, a kinematic structure for the configuration, wherein each kinematic structure comprises an open kinematic chain or a closed kinematic chain.

4. The method of claim 3, wherein performing the configurations analysis comprises analyzing, using at least one processor, the kinematics, statics, and dynamics of each of the configurations.

5. The method of claim 1 , wherein identifying the robot configuration modules comprises determining a plurality of dimensions for the configurations using the design requirements.

6. The method of claim 5, wherein determining the dimensions comprises determining at least one of: a length of a link or a workspace size.

7. The method of claim 1 , wherein determining a mechatronic structure comprises determining at least one of: an actuation system sizing or selection of a mechanical transmission.

8. The method of claim 1 , wherein identifying the design requirements comprises analyzing a target population, a type of therapy, and one or more rehabilitation scenarios.

9. The method of claim 1 , wherein configuring the robot into a first configuration for a first type of rehabilitation therapy comprises configuring the robot for coupled bilateral therapy, and wherein configuring the robot into a second configuration for a second type of rehabilitation therapy comprises configuring the robot for independent bilateral therapy.

10. The method of claim 1 , wherein identifying the robot configuration modules comprises selecting one or more of: a rail module, a leg module, a frame module, and a handle module.

1 1. A system for providing a reconfigurable robot for physical rehabilitation of a subject, the system comprising: a plurality of mechanical modules of different types capable of being assembled into different robot configurations for different physical rehabilitation exercises, the plurality of mechanical modules including: at least one frame module for supporting a structure of the robot configurations; at least one rail module comprising at least one slider, a platform mounted on the at least one slider, and a motor for moving the platform linearly on the at least one slider; at least one leg module including a leg comprising an elongate member and a revolute joint connected to one end of the leg; and at least one handle module for connecting to the rail module or the leg module for allowing a user to move the platform or the leg.

12. The system of claim 1 1 wherein the at least one rail module, the at least one frame module, and the at least one handle module are connectable to each other to form a prismatic joint (P) robot configuration for one degree of freedom therapies.

13. The system of claim 1 1 wherein the at least one rail module comprises two rail modules, the at least one handle module comprises two handle modules respectively connectable to the rail modules, and the rail modules are connectable to the at least one frame module to form a prismatic/prismatic (P/P) robot configuration for one degree of freedom therapies to two limbs of a subject.

14. The system of claim 13 wherein the at least one leg module comprises two leg modules, each comprising a leg having a first end connectable to one of the rail modules via a revolute joint of the leg module to form a prismatic, revolute/prismatic, revolute (PR/PR) robot configuration.

15. The system of claim 14 comprising a third revolute joint for connecting second ends of the first and second legs together to form a prismatic, revolute, revolute, revolute, prismatic (PRRRP) robot configuration.

16. The system of claim 1 1 wherein a first end of the leg is connectable to the rail module via the revolute joint and a second end of the leg is coupled to the at least one handle module to form a prismatic, revolute (PR) robot configuration.

17. The system of claim 1 1 wherein the at least one rail module comprises a belt coupled between the motor and the at least one slider.

18. The system of claim 17 wherein the belt comprises a timing belt.

19. The system of claim 11 wherein the motor comprises a direct current (DC) motor or a quasi-direct drive motor.

20. The system of claim 1 1 wherein the at least one handle module comprises a prismatic (P) handle module for connecting to the platform in a P robot configuration, a revolute (R) handle module for connecting to the platform and the revolute joint in a PR robot configuration, and a PRRRP handle module for connecting to the platform, the revolute joint, and two instance of the leg in a PRRRP robot configuration.