# Simulation and Experimental Study on the Shrub-Cutting Performance of Quasi-Planetary Cutter
## 2 Materials and Equipment
### Equipment
#### 2.2.2 Cutting Test Device  
As shown in Figure 5, a quasi-planetary shrub cutter test device was designed. In addition to the quasi-planetary cutter, it primarily comprises a frame, drive system, feeding system, clamping device, and measuring system [20; 21]. The frame was constructed using 80 \(\times\) 80 mm and 40 \(\times\) 40 mm aluminium profiles from MISUMI, providing high load-bearing capacity and structural stability, which helped minimise vibrations during the shrub-cutting test.  
The drive system utilised a Panasonic servo motor (model MDMF402L1H6M, rated power: 4 kW, rated speed: 2000 r/min, maximum speed: 3000 r/min, was manufactured by Panasonic Corporation, headquartered in Osaka, Japan) as the power source. Power was transmitted to the quasi-planetary shrub cutter via two-star couplings and a U-shaped bracket. A Panasonic servo driver (model MFDLTR3 SF, was manufactured by Panasonic Corporation, headquartered in Osaka, Japan.), controlled by a PC, enabled full control of  
Figure 4: Cutter force analysis.  
Figure 5: Cutting test device.  
the motor's speed, position, and torque through a fully closed-loop control mode. The speed control mode was primarily used in this experiment to adjust the servo motor speed, thereby regulating the cutter's cutting speed.  
The feeding system consisted of two fully enclosed linear modules, powered by a servo motor (model Delta ECMA-C20807 RS, rated power: 0.75 kW, rated speed: 3000 r/min, was manufactured by Delta Electronics, Inc., headquartered in Taoyuan City, Taiwan) and controlled by a Delta servo controller. The feeding speed was precisely regulated via commands from the host PC and was limited by travel switches. The fully enclosed linear modules offered strong dust-proof capabilities, effectively preventing wood chips from entering the modules and causing wear during the shrub-cutting test, thereby ensuring the accuracy of the experiment.  
The clamping device utilised an electric three-jaw chuck to simulate the fixation of shrub roots, ensuring high reliability. It was also equipped with a jaw pressure valve, allowing for automatic clamping without damaging the shrub branches.  
The measuring system employed a DAYSENSOR dynamic torque sensor (model DYN-200, was manufactured by DaySensor, headquartered in Shenzhen City, China) with a torque measurement range of 0-100N-M, a speed measurement range of 0-10,000 r/min, and an error of less than \(\pm\)0.1%. It was paired with a 200 torque measurement system software, which accurately outputted torque, speed, and power data to the PC.  
In the shrub-cutting experiment, the torque signal from the dynamic torque sensor was recorded in real time using a data acquisition system. Prior to contact between the cutter and bush, the torque remains essentially stable at the no-load value, with minimal fluctuations. At the moment of contact, the torque increases sharply and constantly rises during the cutting process, reaching a peak value. Once the bush is fully cut, the torque returns to the no-load level, with minimal fluctuations again. The peak torque (\(M\)) was recorded during the test. As shown in Equations (4) and (5), by processing the torque signal, the cutting force (\(F\)) and cutting power (\(P\)) of the shrub were obtained as follows:  
\[F=\frac{M}{r} \tag{4}\]  
\[P=\frac{2\pi n\int M(t)dt}{t} \tag{5}\]  
where \(M\) is the torque (Mpa); \(r\) is the rotation radius of the quasi-planetary shrub cutter (m); \(n\) is the rotational speed of the quasi-planetary shrub cutter (r/min); \(M(t)\) is the torque sensor curve as a function of time; and \(t\) is the time variable (s).