## 1 Introduction
* _Enhanced training programs_: surgeon training programs emphasize fine motor skills and techniques for minimizing hand tremors [29]. Simulation-based training provides opportunities to practice in controlled environments. Thus, they reduce errors during actual surgeries using dedicated tools [30]. An example of laser applications in the field of eye surgery is laser photocoagulation, which is a precise, minimally invasive ophthalmic procedure utilized for treating various retinal conditions [20]. It involves the application of laser energy to specific areas of the retina in order to create controlled burns or coagulation. These burns help to stabilize or improve retinal health by sealing blood vessels, reducing abnormal growth, or reinforcing retinal adhesion. This type of surgery requires a high level of precision and robotic assistance if performed manually. Advantages of the proposed laser surgical device with vibration compensation include better precision for surgery, availability, as well as flexibility. For the latter two aspects, one can perform surgery in areas where high-performance (e.g., robotic) systems are not available or for emergencies. Drawbacks are related to the dimensions of the system, which is larger than a conventional laser scalpel that only carries an optical fiber for the laser. Numerous studies have approached new methods for tremor attenuation in the surgery field [31; 32], from wearable devices such as bracelets and exoskeletons [33; 34; 35] to robotic approaches. Considering only handheld mechatronics solutions, modified Stewart platforms with or without compliant mechanisms have been utilized for handheld devices capable of hand tremor compensation [36; 37; 35]. This is the approach we have been considering in our line of studies, as well. Other solutions found in the literature are based on bimorph piezo actuators [38] or on microlinear stages [39]. Considering the focal point of the laser as the tool tip for which the hand tremor has the highest impact, an intended laser beam deviation using prisms or acousto-optic deflectors has been studied. Another approach has involved developing extended robotic arms that hold surgical instruments and are controlled directly by the surgeon. The latter solution can blend the precision of robotics with the dexterity and fluidity of human movement. The scope of the above is to design a surgical device capable of minimizing the impact of the surgeon's hand tremor Therefore, it is essential to analyze the specific characteristics of the tremor occurring at the surgeon's hand level, along with its mechanical properties. First, the type of hand tremor that must be considered is physiological, not pathological. This means that it is always present in all people. Such a type of tremor is characterized by its oscillation frequency and by the tremor amplitude. The frequency of the tremor varies from person to person, depending on the biological motor system. It is roughly located in the frequency band of 5 to 15 Hz [40; 41; 42]. The amplitude of the tremor varies, depending on external and internal factors such as emotional state, caffeine level, sleep schedule, etc. For microsurgeons [38], it typically reaches values of 150 \(\upmu\)m peak-to-peak [22; 40; 43], but it does increase with age. A second important aspect of tremor influence is its direction of travel. Tremor appears on all 6 DOF at the hand level (i.e., three translations and three rotations in an orthogonal system positioned at the wrist level) [44; 45; 46]. This becomes challenging for both signal acquisition and processing, especially when it is required to separate the useful signal (i.e., the surgeon's hand movement) from the unwanted signal generated by the tremor. Considering the above, the aim of this work has been to develop a modified Stewart-type platform model with 3 DOF as a proof-of-concept for the proposed surgical device with vibration compensation. The main feature of the proposed device is the compliant structure that allows for fine positioning.