Drives and Controls Magazine
Ball-balancing mobile robot carries flexible pneumatic ‘hand’
Published:  01 July, 2020

The German pneumatics and automation technology manufacturer Festo has unveiled a mobile robot that moves by balancing on a ball, and carries a human-like pneumatic “hand” that can identify items and handle them delicately.

The BionicMobileAssistant is a prototype of an autonomous helper that could assist humans in assembly and intralogistics operations. Balancing on a ball allows the robot to move freely in any direction.

The modular system, developed in collaboration with ETH Zurich, consists of three subsystems: a mobile robot; an electrically-powered robot arm; and the pneumatic gripper – a enhanced version of the BionicSoftHand that Festo first presented in 2019.

The BionicSoftHand 2.0 mimics the movements of the human hand realistically, using tightly integrated valves, sensors, electronics and mechanical components. The fingers and opposable thumb are based on flexible bellows structures with air chambers, surrounded by a firm, yet yielding, knitted fabric. This makes the hand lightweight, adaptive and sensitive, yet capable of exerting strong forces. The fingers are actuated by a compact valve terminal with piezo valves, mounted on the hand.

A 3D-printed wrist with two degrees of freedom allows the hand to move both backwards and forwards, as well as left and right. This means that gripping with a tight radius is possible.

To increase the stability of the fingers, their air chambers contain structural elements that act as bones. For each finger, a bending sensor with two segments determines the positions of the fingertips. The hand wears a glove containing more than 100 tactile force sensors, allowing it to sense an item to be gripped, and to adapt its gripping force accordingly.

A depth camera on the inside of the wrist detects objects and allows the hand to grip a variety of objects, even if they are partially covered. Once the hand has been trained, it can use the data it collects to assess the objects and distinguish good from bad, for example. The information is processed by a neural network, which has been trained in advance.

Festo's BionicMobileAssistant propels itself in any direction by balancing on a ball

The hand is mounted on a lightweight, electric robot arm called the DynaArm. This weighs just 1kg including integrated drive modules, and can carry out fast, dynamic movements.

All the BionicMobileAssistant’s energy supplies are on board, including a battery for the arm and robot, and a compressed air cartridge for the pneumatic hand. Algorithms on the master computer control the system’s autonomous movements. The robot uses two cameras to orient itself independently in three dimensions.

Festo suggests that the BionicMobileAssistant could be used as a service robot, as a helping hand in assembly operations, or to help workers to carry out strenuous or monotonous tasks.

It could also be used in environments where people cannot work because of hazards or restricted accessibility. This could include maintenance or repair work, data measurements or visual inspections.

The mobile robot could also carry out simple tasks in areas where there is risk of infection. For example, it could deliver medicines to patients in hospitals or people requiring care in old people’s homes. It could also carry drinks and food to restaurant tables.

The modular BionicSoftHand 2.0 can be mounted quickly onto other robot arms and is said to be easy to commission. It could, for example, form a completely pneumatic robot system that can work safely with people due to its flexibility and compliance.

A depth camera mounted on the pneumatic hand's wrist helps to identify items being picked up