## 1 Introduction  
Laparoscopic surgery, which is a minimally invasive surgery (MIS) method, began to increase in the early 1990s. It is currently a popular operating technique, whereby surgeons access the body cavities by a small incision instead of a single large one. Tissue manipulation is carried out by special surgical instruments for grasping, holding, cutting, squeezing tissue or a body organ, and suturing. The surgical area is reached through a tiny incision of 3 to 15 mm in width, which is broached through the abdominal wall of the patient over their inflated abdominal cavity. MIS is a type of surgery that minimizes the unnecessary invasion of healthy tissues. It has a number of benefits over traditional open surgery--less postoperative pain owing to the small wound, lower risk of infection, less drug usage, early recovery after the surgical operation leading to shorter hospitalization time, and reduced scarring [1; 2; 3; 4]. The current technology of MIS involves the visualization of the surgical area via video cameras. However, laparoscopic surgery has some significant disadvantages compared to open surgery. The laparoscopic instruments are the only means of contact between the tissue or a body organ and the hands of surgeons. That is why these instruments should be well designed--the pinching force on the surgeon's hand should be a reliable measurement for the grasping force on the grasper jaws. The vision is obtained through incisions in the abdominal walls of the patients using a video camera. The degree of freedom of the laparoscopic instruments limits the surgical working space. In addition, the tactile information such as tissue stiffness and applied force on the tissue is reduced. In the MIS operation, tactile sensing (haptic feedback) is only achieved indirectly through the laparoscopic mechanism. The surgeon's perception of the grasping force may differ from the actual grasping force at the grasper--tissue contact. It increases the risk of injury or damage to the tissue or a body organ due to the excessive force applied by the surgeon. Thus, force feedback is of great importance in laparoscopic surgery. Laparoscopic instruments can be divided into three main groups: purely mechanical instruments, compliant laparoscopic instruments, and laparoscopic instruments with sensors and electronic feedback. The most important scientific works in the field of mechanical laparoscopic graspers include the works of [PERSON] and his collaborators mainly from TU Delft. In the paper [5], the purely mechanical design of a laparoscopic grasper with constant force transmission is presented. There are no standard hinges in the mechanism. It possesses just six rolling kinematic pairs, resulting in very low friction, hysteresis, and substantially reduced backlash. The constant force transmission is achieved through the use of a symmetrical design. The paper [6] is dedicated to the ways of improving the force transmission in laparoscopic grasping instruments by adjusting existing instruments or by designing alternative concepts. The paper [7] presents newly designed, purely mechanical laparoscopic forceps and describes the evaluation of the man-machine interface performance. Another group of laparoscopic instruments is compliant laparoscopic instruments. Moreover, in this field, the scientific works of [PERSON] and his collaborators, from different countries, are among the most important. [PERSON] and [PERSON] [8] were the first to propose the concept of statically balanced compliant mechanisms and studied a compliant mechanism of surgical forceps, which is statically balanced by a low-friction rolling-link compensation mechanism. This mechanism substantially improved the quality of the transmission between the input and output force at the jaws of the grasper, which is negatively affected by the strain energy accumulated by the elastic members of the compliant mechanism. The possibility of extending the building block approach for the design of statically balanced compliant mechanisms is investigated in [9].