Method and system for load estimation and gravity compensation on a robotic arm

A method for load estimation and gravity compensation on a robotic arm, the method to be implemented by a load estimation and gravity compensation system, the robotic arm including at least one joint and a driver module that is installed on the at least one joint, the load estimation and gravity compensation system including a signal processor that is coupled to the driver module, a load estimation module that corresponds with the at least one joint and that is coupled to the signal processor, and a gravity compensation module that is coupled to the load estimation module, the load estimation module including a gravity module correction unit, a virtual robotic arm unit and a computing component, the method comprising steps of:

• operating the driver module in a manipulating mode to move the robotic arm to a first position, and switching the driver module to a location control mode, the robotic arm being subjected to a current load at the first position;
• receiving a first torque signal and a first joint angle outputted by the driver module in the location control mode, the first torque signal being associated with the current load, the first joint angle being associated with the joint at the first position;
• upon receipt of the first torque signal, converting, by the signal processor, the first torque signal into a first torque value;
• upon receipt of the first torque value, generating, by the gravity module correction unit, a set of correction parameters;
• upon receipt of the set of correction parameters and the first joint angle, generating, by the virtual robotic arm unit, a no-load torque value and a maximum-load torque value;
• changing the load subjected to the robotic arm to an unknown load;
• receiving a second torque signal outputted by the driver module, the second torque signal being associated with the unknown load;
• upon receipt of the second torque signal, converting, by the signal processor, the second torque signal into a second torque value;
• estimating, by the computing component, an estimated load value of the unknown load based on the first torque value, the no-load torque value, the maximum-load torque value and the second torque value;
• switching the driver module to a torque control mode, and moving the robotic arm to a second position;
• receiving a second joint angle outputted by the driver module, the second joint angle being associated with the second position;
• and
• generating, by the gravity compensation module, a compensating torque value based on the estimated load value and the second joint angle, and outputting the compensating torque value to the driver module.