The use of a vision system for supervision of a manipulator with electrohydraulic servodrives

The article describes a system for supervising a hydraulic manipulator and allowing its work in the event of failure of the primary measuring system. A monitoring system based on a digital camera observes the manipulator and its environment. In the case of failure of one of the encoders, the control of the manipulator movement is made by taking a feedback signal provided by the vision system. This allows continuation of the work of the manipulator even in the presence of the encoder errors. Additionally, the system is protected against abnormal movements which may lead to hitting of elements allocated in the manipulator working area. A comparison of the system accuracy equipped with two different feedback sensors is also presented.