## 1 Introduction
A Wheatstone bridge circuit is used to measure electrical resistances and calculate the charge [15]. It contains strain gauges, which improve the output signal resolution, compensate for temperature changes and eliminate specific mechanical effects, such as deflections due to asymmetry [11]. The output signal value is determined by a combination of the following factors: geometry of the mechanical elements, the elastic properties, the sensors' location and the AF magnitude on the cell. In the market, the main commercial devices were designed to measure the exerted force by the hand using the MVE method [16; 17; 18]. The choice of measurement technology can significantly impact the accuracy of force measurements, with certain technologies being more suitable for specific types of force measurement than others. In the literature, there are two kinds of devices: commercial devices and devices developed to resolve specific problems for investigation purposes. Commercial devices are used in rehabilitation procedures, e.g., [PERSON] et al. [19] introduced an intriguing device known as the Dyna-8, a portable measurement system enabling users to gather specific numerical data and diagrams on hand and finger forces. This system records the maximum force value through a microcontroller and displays it digitally on an electronic unit. In [20], a finger force sensor adapter is proposed, which measures the maximum grip force control and force tracking task; it monitors and quantifies the patient's process during therapy. Each of these measure effort and torque. In contrast, a force glove system, such as the Force Sensitive Application (FSA) system, the Measure Grip Forces, and the Hand Force Measurement System [21; 22; 23] all directly measure finger forces exerted on an object; they use a sensitive resistor sensor attached to the palmar side of the hand and have high precision in their measurement. However, they limit the natural movements of the hand and fingers in repetitive work, change task conditions and affect productivity; this aspect limits their use when workers perform a high-frequency task with small loads. Therefore, none of them can be used in a production process to measure AF in real time, as required in ergonomic and biomechanical risk assessments. The Body Pressure Measurement System (BPMS) [23] measures pressure distribution throughout the body and support surfaces. Unfortunately, it does not measure triaxial forces; its measurements are perpendicular and unidirectional to the plane. On the other hand, an example of the devices developed to resolve specific problems is the 3D force sensor for biomechanical applications proposed by [PERSON] et al. [24], which aims to integrate sensors in a glove to determine the complete mechanical interaction between the human hand and its environment. The sensor measures the normal force and two perpendicular moments by dividing the read-out into four quadrants. [PERSON] et al. [25] proposed an optical fibre sensor for measuring joint angles. Unfortunately, the sensor is invasive; it measures intra-articular pressure. [PERSON] et al. [22] measured hand/hand grip forces in one-arm drive wheelchairs using the grip force. [PERSON] et al. [26] compared hand grip and resisted wrist extension (using MVC) in terms of amplitude and reproducibility and examined the effect of electrode positioning using electromyography through Ag/AgCl electrodes, which are designed for electrochemistry, stimulation, precision bioelectric recording and electrophysiology; however, this procedure is far from providing accurate information regarding the applied force since it only measures unidirectional muscular load. In a related context, [PERSON] et al. [27] noted a common trend in studies focusing on whole-body manual strength, which often emphasize forces exerted in either the sagittal plane or solely in a vertical direction.