## 1 Introduction
The feasibility of the method is demonstrated in a design of a statically balanced compliant gripper. In [10], a concept, as well as mathematical and finite element modeling of a statically balanced compliant laparoscopic grasper, is presented. This concept not only provides a compliant grasper, which does not need lubrication and avoids friction and energy loss, but it also provided force feedback to eliminate the incorrect laparoscopic pinch force control and tissue damage. A conceptual design and simulation results for two classes of statically balanced compliant micromechanisms are presented in [11]. The authors in [12] presented five criteria that can be used in the static balancing of compliant mechanisms. Their feasibility was proved by three examples using linkages with torsion springs. In the book [13], the author deals with the problem of statically balanced compliant mechanisms. Static balancing eliminates the need for actuation forces besides those required to overcome the inertia and friction of the system. This work has its origins in the work of [PERSON]. During his research in the field of the static balancing of mechanisms using springs, he came up with the idea of applying the same design notion to compliant mechanisms since the flexible elements can be considered as springs. The design of a statically balanced, monolithic, and fully compliant surgical grasper exhibiting equal or better force feedback than conventional surgical graspers is presented in [14]. The use of the pseudo-rigid-body model is shown here for the first time. The case study by [PERSON] et al. published in [15], presents the numerical model and physical prototype of a statically balanced compliant mechanism. It has a nearly zero actuation force during axial deformation owing to a balancer. The third group is laparoscopic instruments with sensors and electronic feedback. The paper [16] reviews the state-of-the-art force and tactile sensing methods and technologies applied in MIS. Several sensing strategies, e.g., displacement-based, current-based, pressure-based, etc., are analyzed. A novel design of an electromechanical grasper enhancing its force-reflecting capability is presented in [17]. A substantial part of the grasper is a tunable spring with optimized haptic and surgical requirements. The tunable spring needs a relatively small motor to be actuated. In [18], local sensors are used to give force feedback, which helps to prevent exceeding forces from causing tissue damage. Obtaining the grasping force by its calculating from the sensor-distributed pressure measurement leads to new control methods [19; 20]. The study [21] focuses on the grasping of a laparoscopic mechanism in order to control the grasping force by using a smart material actuation. The grasper force is controlled through a smart actuator by two types of controllers--the proportional-integral-derivative (PID) and sliding mode controller (SMC). The smart actuator contains a bias spring and a shape memory alloy wire in order to meet the force and displacement requirements. The authors in [22] proposed a laparoscopic grasper driven by inflating a soft pneumatic actuator. At the tip of the grasper, there is a small cylinder with a pneumatic actuator made of silicone and a slider-crank mechanism. The actuator has a built-in strain gauge to measure its displacement. By combining the measurements of the strain gauge and the internal pressure in the pneumatic actuator, it can estimate the grasping force. The paper [23] presents an estimation of grasping force by exploiting the transmission model of the laparoscope surgical robot end-effector with a cable-pulley structure, which considers friction loss between adjacent pulleys. In the study [24], the authors propose a pneumatic system with a novel small soft rotary actuator for a multi-DOF forceps manipulator. The cylindrical cam mechanism transforms the linear motion of the soft actuator into rotary motion.