Postural Control of Living Organisms and Its Engineering Systems
Kazue Nishihara, Mitsuo Wada, and Ryouichi Hashimoto
Industrial Products Research Institute, Agency of Industrial Science and Technology 1-4, Higashi 1-chome, Tsukuba, Ibaraki 305 Japan
Application of the postural control mechanisms to the flexible movemen mechanisms will develop the humaninterface technology which aims to aid and substitute human motor function. In this research study, physiological and biomechanical knowledge of the postural control mechanisms of living bodies are summarized to give basic materials to the future mechanical equilibrating technology. (a) Postural control system of living organisms. The system is composed of four stratified subsystems of spine and brain stem, cerebellum, basal ganglia, and cerebrum. Spinal reflex, which is thought to be a fundamental servo mechanism, maintains automatically man’s standing posture. Brain stem reflex controls posture and dynamical balance of a body to stabilize involuntary motions. Cerebellum, conducting cooperation control of partial motions of the body, adjusts posture and maintains equilibrium. Basal ganglia is thought to be a higher nerve center to stabilize slow and repetitive body actions. Cerebral motor cortex executes fine and subtle controls in voluntary actions. (b) Mechanical equilibrators. Mechanical equilibrafors must be of use in future legged robots travelling on rough terrain surfaces. The following three equilibrators were examined; 1) The leg supporting pivot slides up and down, right and left, 2) The leg supporting pivot has a torque generator, 3) The upper limb is equipped with some reaction mechanisms. (c) Problems of balance and walking controls. Dynamic motion of a leg-body system is achieved by three control modes of leaping hight, posture and balance control. The three modes of the motion control should be realized by the sensor directed parallel and stratified controling architecture. Considering coming aging society, postural control technology in the medical and welfare fields is hopeful of advance in assistance and substitution of man’s lower limb function.