Geometry-aided inversion of manipulator telescopic link length from MEMS accelerometer and rate gyro readings

Abstract

We consider solving telescopic manipulator link length using rate gyros and linear accelerometers. The research is built upon micro-electro-mechanical systems (MEMS) components for low-cost "strap-down" implementation. By formulating a standard inversion problem, the telescopic manipulator's link length is solved with the well-known LevenbergMarquard algorithm in real-time. The inversion is based on linear accelerations of angular motion sensed by a triaxial MEMS accelerometer, which is attached to the tip of the telescopic extension. By fusing the operator control commands for the link extension actuator with the inverted length estimate of the telescopic link, experiments on a hydraulic heavy-duty manipulator demonstrate feasibility of our novel approach.

Forestry crane posture estimation with a two‐dimensional laser scanner

“…In the work by Vihonen et al. (, , , ), the posture of a forestry crane similar to ours is estimated with low‐cost microelectromechanical system IMUs. Their latest work includes an integrated kinematic model for the crane, and it uses multiple accelerometers and gyroscopes attached to the crane boom (Vihonen et al., ).…”

“…The nearest comparable setup found in the state‐of‐the‐art section is the IMU instrumentation of a similar type of a hydraulic crane by Vihonen et al. (, ). Their best results had RMSE of 0.17° for lift and 0.21° for transfer angles as we got 0.14° and 0.40° as our worst test RMSE for the equivalent angles (see Table ).…”

“…The setup can reach up to 1 o accuracy for lift and tilt (referred as transfer in our work) angles and can take bending into account. However, the length of the telescopic extension is significantly more difficult to estimate with only IMUs as Vihonen et al (2014) reported. They can only reach centimeter-level accuracy when the telescopic link is contracted.…”

“…IMU-based solutions usually use one or multiple triaxial accelerometers and gyroscopes to estimate the orientation of the sensor with respect to the earth frame. In the work by Vihonen et al (2013aVihonen et al ( , 2013bVihonen et al ( , 2014Vihonen et al ( , 2016, the posture of a forestry crane similar to ours is estimated with low-cost microelectromechanical system IMUs. Their latest work includes an integrated kinematic model for the crane, and it uses multiple accelerometers and gyroscopes attached to the crane boom (Vihonen et al, 2016).…”

“…However, the length of the telescopic extension is significantly more difficult to estimate with only IMUs as Vihonen et al. () reported. They can only reach centimeter‐level accuracy when the telescopic link is contracted.…”