Four-branch-chain and two-degree-of-freedom rotary parallel mechanism with two continuous rotating axes

Abstract

A four-branch-chain and two-degree-of-freedom rotary parallel mechanism with two continuous rotating axes comprises a fixed platform, a movable platform and four branch chains for connecting the fixed platform with the movable platform, wherein the first branch chain and the second branch chain are of the same structure; one end of each upper connection rod of the first branch chain and the second branch chain is connected with the movable platform through a sphere pair; one end of each lower connection rod of the first branch chain and the second branch chain is connected with the fixed platform through a hook joint; each upper connection rod and the corresponding lower connection rod are connected through a movable pair; the two ends of the third branch chain are connected with the movable platform and the fixed platform through a hook joint and a rotary pair correspondingly, and the axis of the rotary pair is parallel with the axis, close to the fixed platform of the hook joint; and the two ends of a connection rod of the fourth branch chain are connected with the movable platform and the fixed platform through sphere pairs. The axis, close to the fixed platform, of the hook joint of the third branch chain is connected with the center of the sphere pair of the fixed platform through the fourth branch chain, and the axis, connected with the movable platform, of the hook joint is connected with the center of the sphere pair of the movable platform through the fourth branch chain. The mechanism is provided with four supporting branches and can bear large loads, and as the two continuous rotating axes exist, the kinematic calibration and control are easy to implement.

Description

technical field [0001] The invention belongs to the field of robots, in particular to a parallel mechanism. Background technique [0002] The two-degree-of-freedom rotary parallel mechanism is an important branch of the few-degree-of-freedom parallel mechanism. It is used in many occasions, such as attitude adjustment and self-stabilization of platforms on ships, vehicles and aircraft, positioning of medical equipment, cameras and telescopes, and antennas and solar panels. Fields such as azimuth tracking have great application prospects. The two-degree-of-freedom rotating parallel mechanism includes a two-degree-of-freedom spherical mechanism and a two-degree-of-freedom rotating parallel mechanism without a meeting point. The two-degree-of-freedom spherical parallel mechanism proposed in Chinese patent CN200510122178.4 must satisfy the geometry that the axes of the rotating pairs meet at a certain point. Requirements, processing and manufacturing are very difficult; most of...

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Problems solved by technology

The two-degree-of-freedom rotating parallel mechanism includes a two-degree-of-freedom spherical mechanism and a two-degree-of-freedom rotating parallel mechanism without a meeting point. The two-degree-of-freedom spherical parallel mechanism proposed in Chinese patent CN200510122178.4 must satisfy the geometry that the axes of the rotating pairs meet at a certain point. Requirements, processing and manufacturing are very difficult; most of the two-degree-of-freedom parallel mechanisms without meeting points proposed by Chinese patent CN200710061909.8 have a constraint branch that only includes a Hooke hinge, and there are three support branches in total, and the carrying capacity is not large enough

Chinese patent CN201310605981.8 proposes a two-degree-of-freedom parallel mechanism with no meeting point, although it contains four branches, but the mechanism does not have two continuous rotation axes

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