# Controller of Pneumatic Muscles Implemented in Active Seat Suspension
## 1 Introduction
The authors claim that this MPAM provides a simple new option for soft robotic actuation and has the potential to advance the development of soft robotic assistant suits. In another application, [PERSON] et al. propose a novel flat pneumatic artificial muscle made of silicone rubber and embedded fibers [27]. The fibers in the silicone substrate convert radial expansion into axial contraction. The flat PAM with the best structure and performance is fabricated, and a simple wrist exoskeleton is verified under real working conditions. Recent research introduces artificial intelligence (AI) methods in PAM design and modeling, which is crucial for building a PAM controller that meets the required performance and accuracy specifications. [PERSON] et al. created various models for a PAM and evaluated them based on their accuracy in reflecting behavior [28]. Four modeling techniques were utilized: curve or surface fitting, Multi-Layer Perceptron Neural Network, Nonlinear Auto-Regressive, and Adaptive Neuro-Fuzzy Inference System (ANFIS). The results show that the Neural Network model achieves the smallest error among all the models. In the aerospace and automotive industries, PAMs are used for functions such as actuating control surfaces, adjusting wing flaps, or providing assistive forces in vehicle suspensions [29]. Artificial pneumatic muscles, also known as McKibben artificial muscles, are used in various applications, including seat suspension systems. There are three basic types of commonly used seat suspension systems: passive, semi-active, and active. Typically, passive systems include spring and damper elements that protect drivers from harmful vibrations caused by road unevenness. These systems are effective in vibration reduction but only for over-resonant frequencies. However, low-frequency vibrations are amplified by passive systems due to the resonance effect. Semi-active suspensions can partially limit resonant vibrations through ongoing modifications of system stiffness or damping, but active systems are the most efficient for vibration attenuation in the low-frequency range. Although active systems have significant energy demands, they are increasingly used in automotive applications such as seat suspensions. Various actuators (e.g., electromagnetic, pneumatic, hydraulic) can generate the force necessary for active vibration control. PAMs, a type of soft actuator, are progressively used in mechanical engineering. Despite requiring an external air source, their dynamic properties are attractive due to low friction force. Unlike traditional pneumatic cylinders, PAMs have no sliding elements (no piston movement in a cylinder) and operate by creating a tension force during the contraction of retractile tubing (made of rubber material with spirally arranged fibers). Moreover, PAMs are flexible actuators that do not require complex kinematics for the transmission system in a suspension mechanism of limited space. [PERSON] et al. discuss the dynamic modeling of a horizontal seat suspension using pneumatic muscles for active vibration control [30]. The control system presented is based on inverse models of the pneumatic muscles and a controller that calculates the desired active force. Using the dedicated control algorithm, significant vibration reduction transmitted to the human body is achieved. The active seat shows improved performance over the passive system in the 1-10 Hz frequency range. Work machine vibrations significantly impact the health of operators, causing occupational diseases and decreasing work safety. These vibrations lead to fatigue and reduce the ability to efficiently perform specific tasks. Prolonged exposure to a vibrating environment adversely affects brain cortex processes such as perception, thinking, and memory. Even vibrations matching the natural frequencies of various human internal organs and body parts at small amplitudes negatively affect worker health and productivity.