Using UWB Sensor for Delta Robot Vibration Detection

Abstract-This study proposed the ultra-wideband(UWB) sensor to detect the vibration of the delta robot and the distance between UWB sensor and robot arm. Based on the radar propagating principle and the proposed algorithm, the vibration status of robot arm can be obtained. Besides, the vibration status can be reduced by feedback the information to the controller of the robot arm. The advantage of the proposed sensor is that without contacting to the robot arm, UWB sensor is more flexible to be used and will not cause any unnecessary payload as accelerometers. With proper calibration, the simulation of vibration frequency and the real-time absolute position of the robot arm were calculated and demonstrated. The experimental results show that the correlations for measured frequency and distance approximate to 1

Modelling and characterisation of ultrasonic joints for Li-ion batteries to evaluate the impact on electrical resistance and temperature raise

In automotive and stationary Li-ion battery packs, a large number of individual cells, typically hundreds to thousands of cells, are electrically connected to achieve pack specification. These large number of interconnections are mainly achieved by welding cell tab to bus-bar using a welding technique of choice. Ultrasonic metal welding (UMW) is one of the common joining technique employed to join pouch cell’s tabs to bus-bar. Although commonly employed, there is little research currently exist in literature reporting the joint characteristics in terms of electrical resistance and temperature raise due to charge-discharge current. Li-ion batteries reaching sub-milliohm internal resistance, risks the temperature raise at the joint could be even higher than the cell itself which raise a serious safety concern and they are to be addressed. This research investigates the electrical and thermal characteristics of ultrasonic joints of 0.3 mm aluminium/nickel coated copper tabs to 1.0 mm copper bus-bar. This article reports the dynamic behaviour of electrical resistance and corresponding temperature increase as a result of current flow. To capture the electrical and thermal behaviour of the joint, a numerical model has been developed and validated with experimental results, which can be employed to analyse battery pack performance