Beyond Cybathlon: On-demand Quadrupedal Assistance for People with Limited Mobility

Abstract

Background: Assistance robots have the potential to increase the independence of people who need daily care due to limited mobility or being wheelchair-bound. Current solutions of attaching robotic arms to motorized wheelchairs offer limited additional mobility at the cost of increased size and reduced wheelchair maneuverability. Methods: We present an on-demand quadrupedal assistance robot system controlled via a shared autonomy approach, which combines semi-autonomous task execution with human teleoperation. Due to the mobile nature of the system it can assist the operator whenever needed and perform autonomous tasks independently, without otherwise restricting their mobility. We automate pick-and-place tasks, as well as robot movement through the environment with semantic, collision-aware navigation. For teleoperation, we present a mouth-level joystick interface that enables an operator with reduced mobility to control the robot's end effector for precision manipulation. Results: We showcase our system in the \textit{Cybathlon 2024 Assistance Robot Race}, and validate it in an at-home experimental setup, where we measure task completion times and user satisfaction. We find our system capable of assisting in a broad variety of tasks, including those that require dexterous manipulation. The user study confirms the intuition that increased robot autonomy alleviates the operator's mental load. Conclusions: We present a flexible system that has the potential to help people in wheelchairs maintain independence in everyday life by enabling them to solve mobile manipulation problems without external support. We achieve results comparable to previous state-of-the-art on subjective metrics while allowing for more autonomy of the operator and greater agility for manipulation.

Figures (18)

• Figure 1: The proposed system in the two demonstrated environments: (left) on the racetrack of the Cybathlon 2024 competition and (right) in the home of the operator.
• Figure 2: An overview of the proposed system: The system, as presented both at the Cybathlon 2024 competition and in an at-home environment, has two central pillars, which together form the shared autonomy stack. The first pillar, the Manual Control stack (in blue), describes our teleoperation interface. We take the control signal from the operator joystick, the Quadstick, and translate it into control commands for the robot's walking or manipulation controllers. The second pillar, the Automation stack (in green and purple), is application-specific. It handles the autonomous execution of pre-defined tasks after receiving an activation signal from the operator interfaces. The robot can only be in one state at a time, i.e., it is being fully teleoperated or moving fully autonomously. Pictured on the left are two robots and the expert operator, getting into position to solve a task during Cybathlon 2024.
• Figure 3: An overview of the hardware involved in the proposed system, in operation during Cybathlon 2024. The main components are an ANYmal D quadrupedal base and a Duatic DynaArm robotic arm, to which we attach a Robotiq 140F Gripper and an Intel RealSense L515 camera. Attached to the wheelchair of the operator are the QuadStick, which enables them to steer the robot, and the Operator Laptop, which relays critical information between the robot and operator.
• Figure 4: The initial configurations of the two ee Control Modes. The left of the Figure shows the initial configuration of ee Control Mode Front, the right that of ee Control Mode Top. Examples of how the control modes can be used are visible in the two central columns. For ee Control Mode Front, these include picking up a scarf from a chair (at the Cybathlon 2024 February Challenge), pouring water from a carafe into a glass (at home), and opening a mailbox (at the Cybathlon 2024 February Challenge). For ee Control Mode Top, they include picking up a large bottle of water from the floor (at Cybathlon 2024), picking up a straw from a table (at home), and pulling the rack out of a dishwasher (at the Cybathlon 2024 February Challenge).
• Figure 5: The layout of the QuadStick input options is pictured on the left: the central two-axis joystick encoding the vertical and horizontal axes, the three central control channels (marked as 0, 1, and 2), the axis mapping switch control channel to the right, and below them the chin button. On the right, the operator, Samuel Kunz, is pictured using the QuadStick at Cybathlon 2024.