MovableBag+ is a substitutional reality robot offering resistance to impac
t and mobility, designed for boxing training. It employs Encountered-Type
Haptic feedback technology, allowing boxers to train their strikes and foot
work simultaneously. The robot assists or partially substitutes the frequen
t movements and strike training required by coaches, reducing their load.
By integrating VR visual feedback, a multisensory mobile boxing training
system is achieved. The robot comprises a movable base and an inflatable
boxing target. The base is designed with an aluminum octagonal frame, s
urrounded by a buffer pad with space in the middle for the target. It's po
wered by two 24V wheel hub motors, with two omnidirectional wheels for
stability. Through the drive controller, the angular speeds of the right and

left wheels are calculated based on the given linear speed and rotational s
peed, and the linear speed x and rotational speed z are received through t
he WebSocket server. The coach can control the robot through various mo
des in the browser interface, and it provides a Unity SDK for robot motion
control programming. To handle striking force, the base top includes five s
hock absorbers and a pressure-distributing surface matching the boxing t
arget's shape. MovableBag+ aims to provide high load-bearing and mo
bility. Its base weighs 14.3 kg, can reach 18 km/h, and supports approxima
tely 70 kg, enabling the simulation of an 80 kg opponent. A 3D printed Oc
ulus Touch Controller holder, connected to the target, tracks position and
offers haptic feedback in VR applications. A virtual training environment d
esigned in Unity allows the trainer to control MovableBag+'s movement
and the virtual boxer's appearance. The VR controller tracks the position
of the boxing target and glove. When the boxer hits the virtual opponent,
direct haptic feedback from the target is received. The VR controllers trans
mit data to the computer, allowing real-time visual feedback in the virtu