Metamorphic parallel mechanism for ankle joint rehabilitation

Abstract

The invention relates to a metamorphic parallel mechanism for ankle joint rehabilitation. The mechanism comprises a fixed platform, a moving platform, first branch chain, a second branch chain, a third branch chain and a drive system, wherein the first branch chain and the second branch chain have identical structure constitutions; second hook hinged ends of the first branch chain and the second branch chain and the rotating secondary end of the third branch chain are respectively connected with the fixed platform; and first hook hinged ends of the first branch chain and the second branch chain and the third hook hinged end of the third branch chain are correspondingly connected with the moving platform to form a 2-UPU / RPU parallel mechanism. The mechanism is simple in structure, high in rigidity, decoupling in motion part and flexible in motion, motion output at two modes of four freedom degrees of two rotations and two movements and three freedom degrees of two rotations and one movement can be achieved, meanwhile, the rehabilitation process of independent rotation rehabilitation and traction rotation of an angle joint can be achieved, and actions of bending and inward and outward turning of back toes of the angle joint, up pushing and down pulling and front and back traction can be achieved.

Description

technical field [0001] The invention belongs to the field of robots, in particular to a metamorphic parallel mechanism suitable for rehabilitation of ankle joints. Background technique [0002] Parallel mechanism has attracted more and more scholars' attention and research because of its high mechanism stiffness, strong bearing capacity, small motion inertia and small cumulative error. Among them, the parallel mechanism with less degrees of freedom, that is, the parallel mechanism with degrees of freedom from 2 to 5, has the advantages of fewer components, relatively simple control, and easy manufacturing. In many industrial fields that do not require 6 degrees of freedom, such as astronomical telescopes, tracking flying targets, cameras, It is very useful in the adjustment of sea surface operation platform, medical equipment and other fields. [0003] The ankle joint is one of the three major joints of the lower limbs of the human body. It is an important hub and load-bear...

AI Technical Summary

Problems solved by technology

For A-type mechanisms such as Chinese Patent 201110136484.9, Chinese Patent 201620254272.9, and Chinese Patent 201620254274.8), only the two-rotation mechanism that can realize dorsiflexion / lame flexion and adduction / abduction can only partially meet the requirements of ankle joint rehabilitation, and has a single function, which is difficult to achieve. Realize the fixed installation of the motor, which increases the inertia of the whole mechanism and also increases the load on the patient's ankle joint

For category B, such as Chinese patent: 201310421566.7 The redundant degrees of freedom in the mechanism cause additional force on the patient, which violates the comfort criteria that should be paid attention to in the design of rehabilitation institutions. At the same time, redundant drives lead to waste of power and increase the difficulty of control.

For category C such as Chinese patent 201310006399.X, Chinese patent 201010600198.9, Chinese patent 201110369691.9, Chinese patent 201420558374.0, Chinese patent 201510381350.1, 3-RSS / S, 3-UPS / RRR, 2-PSS / S, 2-UPS / Parallel mechanisms such as UCU / S and 3-RRRPP are used as ankle joint rehabilitation institutions. Although these institutions meet the requirements for degrees of freedom in rehabilitation training, they require the intersection of the three axes at the same point, which requires high installation accuracy, or cannot guarantee the degree of freedom of the mechanism. The axis of rotation coincides with the axis of the ankle joint of the human body. During the rehabilitation process, the ankle joint rotates with the mechanism, and the calf needs to follow suit. If the calf is not well coordinated, the recovery progress will be affected and secondary injuries may occur

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