# Electromechanical Actuator-Based Solution for a Scissor Lift

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## Abstract

**:**

## 1. Introduction

## 2. The Reference System—Scissor Lift

#### 2.1. Overview of Test Arrangements

#### 2.2. Utilized Duty Cycles

## 3. Model and Validation of the Reference System

#### 3.1. Hydraulic Components

_{p}is the pump displacement [m

^{3}/rad], ω

_{p}is the angular speed of the motor [rad/s], calculated using the mechanical characteristic of the motor, a is the leakage coefficient [m

^{3}/Ns], p

_{p}is the pressure on the pump outlet [N/m

^{2}], and c

_{1}is the hydraulic capacity of the line [m

^{5}/N]. Q

_{R}is the oil flow to an indirect branch through the flow regulator in [m

^{3}/s] and is calculated using a flow equation:

_{D}[m

^{2}] is the cross-sectional area of the valve orifice, c

_{D}[-] is the coefficient of flow losses, ρ [N/m

^{3}] is the density of the hydraulic liquid, Δp [N/m

^{2}] is the pressure drop between the inlet and outlet of the valve, and x

_{R}is the signal of the valve control [-]. Q

_{R1}is the oil flow to the tank through the flow regulator in [m

^{3}/s], and Q

_{z}is the flow through a normally closed pressure relief valve in [m

^{3}/s], described by the equation:

_{z}is the gain coefficient [m

^{5}/Ns], and p

_{z}is the valve opening pressure in [N/m

^{2}].

_{R2}is the oil flow through the directional valve [m

^{3}/s], c

_{2}is the hydraulic capacity of the hydraulic line [m

^{5}/N], p

_{1}is the pressure in the line in [N/m

^{2}], and p

_{s}is the pressure on the hydraulic actuator inlet in [N/m

^{2}].

_{3}is the hydraulic capacitance of the third hydraulic line in [m

^{5}/N], v

_{s}is the speed of the piston rod in [m/s], and D is the diameter of the piston in [m].

_{s}is the movement of the piston rod [m], f

_{s}is the viscous resistance factor [Ns/m], F

_{R}is the force on the support in the lower piston position in [N], and m(x

_{s}) is the effective mass of the platform reduced to the piston rod in [kg].

_{Q}is the mass of the load [kg], m

_{ppr}is the mass of the piston and piston rod in [kg], and i is the transmission ratio of the mechanical system of the scissor lift [-]. The total force acting on the actuator was calculated according to the formula:

_{s}) is the effective load of the platform reduced to the piston in [N].

_{s}) and F(x

_{s}) depend on the transmission ratio i of the mechanical system, which was determined experimentally and described by the approximate equation and demonstrated in Figure 4.

_{p}is the lifting speed of the platform and x

_{p}is the lifting height of the platform.

#### 3.2. Electric Drive

_{a}is the armature inductance in [H], R

_{a}is the armature resistance in [Ohm], K

_{t}is the torque coefficient in [Nm/A], J

_{a}is the inertia of the motor in [kg/m

^{2}], B

_{a}is the damping factor [Wb], and K

_{b}is the back EMF (electromotive force) coefficient in [V/rad/s]. The DC motor transfer function is formed from the above equations by converting from the time-domain to the s-domain. For validation of the DC motor model, refer to the following section.

#### 3.3. Model Validation

- Displacement of piston rod x
_{s_exp}, - Height of the platform x
_{p_exp}, - Pressure p
_{s_exp}, and - Consumed electric motor power P
_{exp}.

_{kavg}:

_{kavg}are presented in Table 2.

#### 3.4. Results of the Analysis of Conventional Hydraulics

_{o}consumed by the hydraulic system of the scissor jack consists of the energy losses to supply the valve coils E

_{v}, the energy losses in the motor-pump system E

_{m}, the energy losses in the hydrostatic system E

_{h}, and the effective energy E

_{e}. The overall energy is calculated as follows:

_{R}is the signal of the valve control (in the discrete interval x

_{R}= [0, 1], respectively, for the coil power off and on) and P

_{coil}= 30 W is the power supply to the valve coil.

_{mp}is the efficiency of the motor-pump system.

_{h}are defined as

_{e}to input energy E

_{o}. Sankey diagrams were built utilizing Equations (18)–(21), and Figure 10 illustrates an example of it for a 96-kg payload during the lifting stage. The Sankey diagram is based on a validated simulation study for the scissor lift.

_{m}and energy losses in the hydrostatic system E

_{h}.

## 4. Proposed EMA-Based Scissor Lift

#### 4.1. An Overview of the Test Arrangements

#### 4.2. EMA Model

#### 4.3. EMA Model Validation

## 5. Analysis and Discussion

#### 5.1. Power and Energy Consumption Analysis

_{p}for the CH- and EMA-based solutions with 0 kg, 96 kg, and 205 kg payloads for the lifting operation. As can be seen in the figure, there is an acceptable result between height and velocity values, and the simulation results can be utilized for further analysis.

#### 5.2. Techno-Economic Analysis

## 6. Discussion and Future Outlook

## 7. Conclusions

## Author Contributions

## Funding

## Data Availability Statement

## Conflicts of Interest

## References

- Viaggi, R. Annual Economic Report; CECE: Brussels, Belgium, 2021; Available online: https://www.cece.eu/stream/cece-annual-economic-report-2021 (accessed on 14 May 2023).
- Emission Standards: Europe: Nonroad Engines. dieselnet.com. Available online: https://dieselnet.com/standards/eu/nonroad.php (accessed on 14 May 2023).
- Fassbender, D.; Zakharov, V.; Minav, T. Utilization of Electric Prime Movers in Hydraulic Heavy-Duty-Mobile-Machine Implement Systems. Autom. Constr.
**2021**, 132, 103964. [Google Scholar] [CrossRef] - Abuowda, K.; Okhotnikov, I.; Noroozi, S.; Godfrey, P.; Dupac, M. A Review of Electrohydraulic Independent Metering Technology. ISA Trans.
**2020**, 98, 364–381. [Google Scholar] [CrossRef] [PubMed] - Donkov, V.H.; Andersen, T.; Linjama, M.; Ebbesen, M. Digital Hydraulic Technology for Linear Actuation: A State of the Art Review. Int. J. Fluid Power
**2020**, 21, 263–304. [Google Scholar] [CrossRef] - Digital Displacement® Pumps. Available online: https://www.danfoss.com/en/products/dps/pumps/digital-displacement-pumps/digital-displacement-single-and-multiple-outlet-pumps/ (accessed on 14 May 2023).
- INNAS—Fluid Power Innovation. Available online: https://www.innas.com/index.html (accessed on 14 May 2023).
- Axial Piston Pumps AX. Bucher Hydraulics. Available online: https://www.bucherhydraulics.com/en/products/pumps-and-motors/pumps/axial-piston-pumps-ax (accessed on 14 May 2023).
- NorrDigi—Energy Saving Motion Control. Available online: https://www.norrhydro.com/en/norrdigi-digital-hydraulic-solution (accessed on 14 May 2023).
- Minav, T.A.; Heikkinen, J.E.; Pietola, M. Electric-Driven Zonal Hydraulics in Non-Road Mobile Machinery. In New Applications of Electric Drives; Intechopen: Rijeka, Croatia, 2015. [Google Scholar] [CrossRef]
- Koitto, T.; Kauranne, H.; Calonius, O.; Minav, T.; Pietola, M. Experimental Study on Fast and Energy-Efficient Direct Driven Hydraulic Actuator Unit. Energies
**2019**, 12, 1538. [Google Scholar] [CrossRef] - Qu, S.; Fassbender, D.; Vacca, A.; Busquets, E. A High-Efficient Solution for Electro-Hydraulic Actuators With Energy Regeneration Capability. Energy
**2021**, 216, 119291. [Google Scholar] [CrossRef] - Qiao, G.; Liu, G.; Shi, Z.; Wang, Y.; Ma, S.; Lim, T.C. A Review of Electromechanical Actuators for More/All Electric Aircraft Systems. Proc. Inst. Mech. Eng. Part C J. Mech. Eng. Sci.
**2017**, 232, 4128–4151. [Google Scholar] [CrossRef] - Hagen, D.; Padovani, D.; Choux, M. Guidelines to Select Between Self-Contained Electro-Hydraulic and Electro-Mechanical Cylinders. In Proceedings of the 2020 15th IEEE Conference on Industrial Electronics and Applications (ICIEA), Kristiansand, Norway, 9–13 November 2020. [Google Scholar] [CrossRef]
- EX02—Prototype Electric Excavator. Available online: https://www.volvoce.com/global/en/this-is-volvo-ce/what-we-believe-in/innovation/prototype-electric-excavator/ (accessed on 14 May 2023).
- eFuzion: Innovative Technology for a Sustainable Future. YANMAR. Available online: https://www.yanmar.com/global/about/ymedia/article/efuzion.html (accessed on 14 May 2023).
- DaVinci AE1932 All-Electric Scissor Lift. Available online: https://www.jlg.com/en/equipment/scissor-lifts/electric/davinci-series-scissor-lifts/ae1932 (accessed on 14 May 2023).
- New All-Electric Bobcat Compact Track Loader Breaks Fresh Ground. Industrial Vehicle Technology International. Available online: https://www.ivtinternational.com/news/hybrid-electric-vehicles/new-all-electric-bobcat-compact-track-loader-breaks-fresh-ground.html (accessed on 14 May 2023).
- Inc, Moog Construction Article: Komatsu’s All Electric Wheel Loader Prototype in Partnership with Moog at Bauma 2022. Available online: https://www.moogconstruction.com/News/komatsu-s-all-electric-wheel-loader-prototype-in-partnership-wit.html (accessed on 14 May 2023).
- VÖGELE. Bauma 2022|New Mini Road Pavers from VÖGELE. Available online: https://www.wirtgen-group.com/en-fi/news/voegele/mini-500e-and-mini-502e/ (accessed on 14 May 2023).
- Bao, Z. Study on Simulation of System Dynamic Characteristics of Hydraulic Scissor Lift Based on Load-Sensing Control Technology. IOP Conf. Ser. Mater. Sci. Eng.
**2019**, 612, 042036. [Google Scholar] [CrossRef] - Stawiński, Ł.; Kosucki, A.; Morawiec, A.; Sikora, M. A New Approach for Control the Velocity of the Hydrostatic System for Scissor Lift with Fixed Displacement Pump. Arch. Civ. Mech. Eng.
**2019**, 19, 1104–1115. [Google Scholar] [CrossRef] - Motiomax by Norrhydro. Available online: https://www.norrhydro.com/en/motiomax (accessed on 14 May 2023).
- Electricity Prices. Global Petrol Prices. Available online: https://www.globalpetrolprices.com (accessed on 14 May 2023).

**Figure 4.**Transmission ratio i of the mechanism and lifting height of the platform x

_{p}as a function of the piston rod displacement x

_{s}.

**Figure 10.**The Sankey diagram for a conventional scissor lift with a payload of 96 kg during a single lifting cycle.

**Figure 11.**(

**a**) Utilized EMA actuator, adopted from [23], (

**b**) EMA-based solution for a scissor lift, and (

**c**) Schematic of EMA-based system.

**Figure 16.**The consumed (system) power P from the battery for the EMA-based (

**A**) and CH-based (

**B**) solutions for the single lifting cycle.

**Figure 17.**Comparison of the energy consumption for the CH- and EMA-based solutions for the single lifting cycle.

Component | Main Parameters |
---|---|

Pump | q_{p} = 3.8 cc/rev; p_{n} = 210 bar |

Cylinder | D = 80 mm; stroke length = 800 mm |

DC motor | Voltage: 24 V; P_{n} = 3 kW; n_{n} = 4500 rpm |

96 kg | 205 kg | |||
---|---|---|---|---|

Parameter | Average Difference between Simulation and Experimental | W_{avg} [%] | Average Difference between Simulation and Experimental | W_{avg} [%] |

x_{s} [m] | 0.0115 | 1.44 | 0.0083 | 1.04 |

p_{s} [bar] | 10.82 | 6.01 | 5.32 | 2.96 |

x_{p} [m] | 0.07 | 1.46 | no exp. data | |

P_{el} [W] | 113.24 | 2.83 | 182.45 | 4.56 |

Parameter | 0 kg | 96 kg | 205 kg |
---|---|---|---|

E_{o} [kJ] | 52.2 | 56.9 | 63 |

E_{v} [kJ] | 0.56 | 0.57 | 0.60 |

E_{m} [kJ] | 8.25 | 9.02 | 9.98 |

E_{h} [kJ] | 18.03 | 18.17 | 18.40 |

Ee [kJ] | 25.34 | 29.17 | 34.01 |

η [%] | 48.6 | 51.2 | 54 |

Component | Main Parameters |
---|---|

Mechanical cylinder | Stroke 800 mm Lead 0.64 mm/rev |

DC motor | Voltage: 24 V; P_{n} = 4 kW; n_{n} = 3000 rpm |

**Table 5.**Comparison of work duration between conventional hydraulics- and electromechanical actuator-based systems with a fully charged battery in an ideal case scenario.

Payload, kg | Conv. Sys. Number of Cycles | EMA. Sys. Number of Cycles |
---|---|---|

96 | 344 | 592 |

205 | 311 | 462 |

**Table 6.**Comparison of expenses between conventional hydraulics and electromechanical actuator-based systems for 200 days per year.

Country | Electricity Price, C/kWh | Payload, kg | Conv. Sys. Expenses, EUR | EMA. Sys. Expenses, EUR | Economy, % |
---|---|---|---|---|---|

Poland | 0.177 | 96 | 146.67 | 85.15 | 41.95 |

205 | 162.25 | 109.03 | 32.81 | ||

Finland | 0.418 | 96 | 346.38 | 201.09 | 41.95 |

205 | 383.17 | 257.49 | 32.81 |

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## Share and Cite

**MDPI and ACS Style**

Stawiński, Ł.; Zakharov, V.; Kosucki, A.; Minav, T.
Electromechanical Actuator-Based Solution for a Scissor Lift. *Actuators* **2023**, *12*, 394.
https://doi.org/10.3390/act12100394

**AMA Style**

Stawiński Ł, Zakharov V, Kosucki A, Minav T.
Electromechanical Actuator-Based Solution for a Scissor Lift. *Actuators*. 2023; 12(10):394.
https://doi.org/10.3390/act12100394

**Chicago/Turabian Style**

Stawiński, Łukasz, Viacheslav Zakharov, Andrzej Kosucki, and Tatiana Minav.
2023. "Electromechanical Actuator-Based Solution for a Scissor Lift" *Actuators* 12, no. 10: 394.
https://doi.org/10.3390/act12100394