A 4-DOF Workspace Lower Limb Rehabilitation Robot: Mechanism Design, Human Joint Analysis and Trajectory Planning

Abstract

<jats:p>Most of currently rehabilitation robots cannot achieve the adduction/abduction (A/A) training of the hip joint and lack the consideration of the patient handling. This paper presents a four degrees of freedom (DOF) spatial workspace lower limb rehabilitation robot, and it could provide flexion/extension (F/E) training to three lower limb joints and A/A training to the hip joint. The training method is conducting the patient’s foot to complete the rehabilitation movement, and the patient could directly take training on the wheelchair and avoid frequent patient handling between the wheelchair and the rehabilitation device. Because patients own different joint range of motions (ROM), an analysis method for obtaining human joint motions is proposed to guarantee the patient’s joint safety in this training method. The analysis method is based on a five-bar linkage kinematic model, which includes the human lower limb. The human-robot hybrid kinematic model is analyzed according to the Denavit-Hartenberg (D-H) method, and a variable human-robot workspace based on the user is proposed. Two kinds of trajectory planning methods are introduced. The trajectory planning method and the human joint analysis method are validated through the trajectory tracking experiment of the prototype.</jats:p>

Research on 4-UPUS Parallel Mechanism Ankle Joint Rehabilitation Training Robot

“…It can perform rehabilitation training in dorsiflexion/plantarflexion and varus/valgus directions, calibrate the control accuracy of the kinematic model and derive the inverse solution of the position [29].Wang H. proposed a four-degree-of-freedom lower limb rehabilitation robot, which analyzed the human-machine hybrid kinematics model according to the Denavit-Hartenberg (D-H) method, and explored the user-based variable human-machine workspace. The trajectory tracking experiment of the prototype verifies the trajectory planning method and the human body joint analysis method [30].Based on the theory of generalized function set, Zhang J. reveals the relationship between the motion characteristics of a rigid body and a point on the rigid body. It is determined that the robot body can realize the motion characteristics of the six-dimensional ankle [31].…”

Parameter Calibration on Replacement Manipulator for UHV Valve-Side Bushing Based on Spinor Theory

“…At present, D-H parameter method is commonly used in manipulator calibration to establish kinematics model because its method is simple and easy to use. e D-H parameter method is used to establish the kinematic model in reference [27][28][29][30], but the D-H parameter method has a defect that cannot be ignored, that is, its motion can only revolve around the x-axis and z-axis, but cannot express the motion about the y-axis [26], which makes the singularity problem when the two continuous joints are parallel or nearly parallel, and the calculation process of the kinematic model of the manipulator with multidegree of freedom is complex and inefficient. In view of the shortcomings of the D-H parameter method, the MDH method has good kinematic characteristics and can find the forward and inverse solutions of the kinematic model [13,[31][32][33], but the singularity problem is still a great challenge.…”

Robot-Assisted Rehabilitation Architecture Supported by a Distributed Data Acquisition System

“…Some of these reported robots operate in a two-dimensional (2D) environment [ 13 ]. In contrast, others operate in a three-dimensional (3D) environment with 3 Degrees of Freedom (DOF) [ 14 ], 4 DOF [ 15 ], 5 DOF [ 9 , 16 ], 6 DOF [ 12 ], and a few even reached 7 DOF or more [ 17 ]. Some research teams have focused on developing algorithms for using dedicated commercial robots in the industrial domain [ 18 , 19 ].…”