Effective Nonlinear Control Algorithms for a Series of Pneumatic Climbing Robots

Aimed at combining the advantages of the lightweight mechanism and the passive compliant movement, pneumatic actuators are used to drive a series of climbing robots to meet the requirements of glass-wall cleaning for high-rise buildings. The pneumatic systems in Sky Cleaners include X, Y and Z cylinders, brush cylinders and the vacuum suckers. The major challenge in the pneumatic systems is the ability of a control system to deal with hysteresis which is caused by coulomb friction, temperature, and manufacturing tolerance stack up of the valves. Three nonlinear control strategies, fuzzy PID, segmental proportional control, and segmental variable bang-bang controller are proposed for Sky cleaner 1, 2, 3 respectively in order to solve the problems of high speed movement and precise position control of the cylinders. Testing results show that the novel approaches can effectively improve the control quality.