Kinematics of platform stabilization using a 3-PRS parallel manipulator

Abstract

In this paper, a 3-PRS (prismatic, revolute, and spherical) parallel manipulator for platform stabilization is designed. The main purpose of this device is to stabilize visual equipment, which is placed on top of a car to inspect electrical transmission cables, as part of routine maintenance. Due to the bulky and heavy infrared cameras used during inspections, a stabilizer platform has been designed to handle the weight of camera equipment up to 10 kg. This device consists of two major mechanisms. The first mechanism is able to adjust the angle of the camera. Thus, the user can focus the camera along the electric transmission lines. The second mechanism is stabilization. The mechanism serves to stabilize the orientation and position of the camera in the roll, pitch, and heave directions. To test the performance of the stabilization mechanism, the device is fed with the known value of the angle with regard to the input. As such, the device is trying to compensate for the change in angle. The results show that the errors between the input angles and compensated angles are in the range of 0.4–3%. Errors are seen to be within an acceptable range. It is significant that the resultant errors do not affect the orientation of the camera.

Parasitic Motions of 3-PRS Parallel Mechanisms with Two Different Branch Chain Arrangements

“…According to Equations ( 8)- (10), it is known that the moving platform S 1 S 2 S 3 produces one rotation φ and two translation movements, x and y, of the moving platform center point O m along the x and y axes.…”

“…The most famous 2R1T PM may be the 3-RPS PM proposed by Hunt [8], where R denotes a revolute pair, P a prismatic pair, and S a spherical joint. The 3-RPS PM or its variant, 3-PRS PM, has attracted much attention, and has broad application prospects and potential in industrial fields [9,10]. Research was performed regarding kinematics analysis [11,12], dimensional synthesis [13][14][15], singularity [16], and dynamics [17,18].…”