Faulhaber Drives Assist Robotic Glove Operation

Musculoskeletal disorders are a common occupational disease in the EU and North America and are one of the most common causes for long- term absence from work. Work-related upper-limb disorders annually cost 2.1 billion euros across the EU and are responsible for 45% of all occupational diseases. Wearables, clothing enhanced through technology, offer an approach for reducing these injuries. Ironhand from the Swedish company Bioservo Technologies is a soft robotic glove that strengthens the human grip with help of the company’s patented SEM technology. The gripping force support of the individual fingers is made possible with Faulhaber drives.

At the EU level, repetitive work is the greatest risk factor. 74% of employees in the EU spend at least 25% of their working time performing repetitive arm or hand movements. According to the German Federal Institute for Occupational Safety and Health, musculoskeletal disorders are the most common cause for limited capabilities on the job, severe disabilities, early retirement, and temporary incapacity to work. According to a survey performed by the European Agency for Health and Safety at Work, 45% of those surveyed suffer from painful or fatiguing positions at work, 25% from back pain and 20% from muscle pain. Studies show that, every second worker could be affected by musculoskeletal-related disorders by 2030.

Work-related disorders of the neck and upper extremities affect the throat, shoulders, arms, hands, wrists and fingers and cause tingling, numbness, discomfort, or pain. The use of vibrating tools or coldness can worsen these problems. The effects are reduced mobility or grip strength. Both can cause additional dangers during work, for example if an employee can no longer safely hold or operate a tool. Furthermore, demographic change means that society is becoming older as a whole and will remain in active working life longer. Improved ergonomics at the workplace are therefore increasingly important – both for healthy people as well as for those who are already physically disabled. In addition to solutions that make the actual workplace, e.g., the workbench, the desk or the assembly line, more ergonomic, companies increasingly rely on solutions that can be used to augment people. Exoskeletons which are worn on the body like clothing, are one solution.

Ironhand is a soft, active exoskeleton for the hands and fingers. Normally, a gripping action is made possible by the muscles in the lower arm and hand. These muscles pull on tendons, thereby moving the fingers. Ironhand functions in a similar way: pressure-sensitive sensors in the fingertips of the glove detect the gripping action that the user performs with his or her hand. A computer integrated in the system calculates the additional gripping force that is necessary and small servomotors pull thin cables in the fingers. The higher the pressure on the sensors, the more power delivered by Ironhand. The settings of the glove can be adapted according to personal preferences as well as the type of work being performed. Data functions enable a digital risk assessment of the hand and the integration of the user in an Industry 4.0/factory-of-the-future concept. Grip-intensive applications with high ergonomic risk can be identified by analyzing the data during practical work and users can take appropriate countermeasures.

The glove is available in four different sizes and can be worn by left- and right-handed users. The battery pack, which is worn like a backpack, contains both a computer unit as well as the motors that control the individual fingers. Users can preset various profiles that contain different combinations of sensor sensitivity, force, finger symmetry and locking tendency. To change the profile, the user only needs to press a button on the remote control, which is located in the chest area.

By means of this profile, it is possible, for example, to flexibly respond to different requirements encountered during the course of the workday. Such as if a person performs slightly stressful tasks during the morning followed by activities in the afternoon that place heavy strain on the muscles. This also allows both male and female users to work with one system. Within milliseconds, the system can provide up to 80 N of gripping force.

The system is designed so as not to impede the wearing of personal protective equipment (PPE), such as gloves, fall-protection devices, helmets, or warning clothing. For breaks, it can be put on and taken off without external help. The capacity of the batteries in the power supply is designed for a typical working day.

To control the individual fingers, Bioservo uses DC-micromotors with graphite commutation of the 1741 … CXR series in their Ironhand. The series combines power, robustness and control in a compact form. This is ensured by graphite commutation, high quality neodymium magnets and the tried-and-tested winding of the Faulhaber rotor. The powerful neodymium magnet gives the motors a high power density with a continuous torque ranging from 3.6 to 40 mNm. The impressive performance data and the compact size open up a wide spectrum of possible applications at an optimized price/performance ratio.