Active balancing and turning for alpine skiing robots

Abstract

This paper presents our preliminary research into the autonomous control of an alpine skiing robot. Based on our previous experience with active balancing on difficult terrain and developing an ice-skating robot, we have implemented a simple control system that allows the humanoid robot Jennifer to steer around a simple alpine skiing course, brake, and actively control the pitch and roll of the skis in order to maintain stability on hills with variable inclination.The robot steers and brakes by using the edges of the skis to dig into the snow, by inclining both skis to one side the robot can turn in an arc. By rolling the skis outward and pointing the toes together the robot creates a snowplough shape that rapidly reduces its forward velocity.To keep the skis in constant contact with the hill we use two independent proportional-integral-derivative (PID) controllers to continually adjust the robot’s inclination in the frontal and sagittal planes.Our experiments show that these techniques are sufficient to allow a small humanoid robot to alpine ski autonomously down hills of different inclination with variable snow conditions.

Stability Control and Turning Algorithm of an Alpine Skiing Robot

“…However, even with such a navigation algorithm, it is impossible to properly follow the gate unless stability control is applied. In [10], the robot was prevented from falling by using posture control. However, by simply controlling the posture of the robot, it can easily fall when the slope change was abrupt or it moves with a tiny turn radius.…”

“…However, it is difficult to realize the properties of the real snow in a simulator. Therefore, most of the researchers have conducted real experiments to try to verify their algorithms [9,10,11]. Some researchers said that there is no simulation tool that can accurately reflect the models of the skiing robot, the ski, and the terrain in real-time.…”

“…By considering the relationship between joint motions, the skiing robot could turn on the slope by abduction–adduction motion. Iverach-Brereton et al used a humanoid robot to verify their braking motion and the performance of posture control in a snowy environment while using proportional-integral-derivative (PID) controllers [10]. In addition, ZMP has been applied to maintain stability during skiing and realize the navigation algorithm while using cameras [11,12,13,14].…”

“…Unfortunately, there are no simulation tools that can realize the precise properties of snow. Roller skis were used to test the skiing robot in a real environment to overcome this problem, but the experiments with roller-skis did not work well, because roller skis with wheels are not suitable for carving turns [10].…”

Carved Turn Control with Gate Vision Recognition of a Humanoid Robot for Giant Slalom Skiing on Ski Slopes

“…In 2017, the University of Manitoba studied the balancing and turning of skiing robots using a 45 cm tall, small humanoid robot. The study revealed that these robots could readily turn around actual snow slopes using simple controllers that control only the angle of the torso without ZMP calculation [ 33 ]. In 2019, Ajou University conducted a Webot simulation of ski balancing and turning with a 45 cm tall, small humanoid robot.…”