Joint device with the following features: - an electric motor for causing a relative movement between a joint driving side and a driven joint side, - a motor driver, which is designed to supply the electric motor with energy or to discharge energy, - a motor connection device, which is designed to guide the energy exchange in an unaffected way between the motor control unit and the electric motor in the normal state, to short circuit continuously or in a pulsed manner in a short-circuit condition of the electric motor, - a mechanically acting, electrically controllable locking device, which blocks a relative movement between the joint driving side and the driven joint side in a positive-locking locked position when not energized and, in a release position when energized, releases this relative movement, - a control unit, which is designed to control the motor driver, the motor connection device, and the locking device depending on different operating states in a way such that the joint device is stoppable, - a motor connection control unit, which is designed to control the motor connection device and the locking device in different ways so that the joint device is stoppable, - the control unit comprises an operating state determination unit, which is connected to a number of sensor devices and is designed to determine different operating states, - wherein the joint device is designed to cause its stoppage through the following alternative methods: - in a first alternative, if no errors are present in the control unit, then the motor driver is used for braking the electric motor, - in a second alternative, if errors are detected outside of the control unit by the operating state determination device, then the motor driver is controlled by the control unit to brake the electric motor and at a later point in time, however, at most after a predetermined dead time, the locking device is displaced into the locked position, - in a third alternative, if the control unit is determined to be defective by the motor connection control unit, then the motor connection device is shifted into the short circuit condition and at a later point in time, however at the latest after a predetermined dead time, the locking device is displaced into the locked position, - in a fourth alternative, if a power failure is present yet is not detectable, then the locking device is displaced into the locked position due to the lack of a power supply. - an electric motor for causing a relative movement between a joint driving side and a driven joint side, - a motor driver, which is designed to supply the electric motor with energy or to discharge energy, - a motor connection device, which is designed to guide the energy exchange in an unaffected way between the motor control unit and the electric motor in the normal state, to short circuit continuously or in a pulsed manner in a short-circuit condition of the electric motor, - a mechanically acting, electrically controllable locking device, which blocks a relative movement between the joint driving side and the driven joint side in a positive-locking locked position when not energized and, in a release position when energized, releases this relative movement, - a control unit, which is designed to control the motor driver, the motor connection device, and the locking device depending on different operating states in a way such that the joint device is stoppable, - a motor connection control unit, which is designed to control the motor connection device and the locking device in different ways so that the joint device is stoppable, - the control unit comprises an operating state determination unit, which is connected to a number of sensor devices and is designed to determine different operating states, - wherein the joint device is designed to cause its stoppage through the following alternative methods: - in a first alternative, if no errors are present in the control unit, then the motor driver is used for braking the electric motor, - in a second alternative, if errors are detected outside of the control unit by the operating state determination device, then the motor driver is controlled by the control unit to brake the electric motor and at a later point in time, however, at most after a predetermined dead time, the locking device is displaced into the locked position, - in a third alternative, if the control unit is determined to be defective by the motor connection control unit, then the motor connection device is shifted into the short circuit condition and at a later point in time, however at the latest after a predetermined dead time, the locking device is displaced into the locked position, - in a fourth alternative, if a power failure is present yet is not detectable, then the locking device is displaced into the locked position due to the lack of a power supply.