engineering manager mobile systems and electronics busquets.pdfdc-mh/eng5-na | 29/05/2019 © bosch...

DC-MH/ENG5-NA | 29/05/2019

© Bosch Rexroth AG 2019. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.1

Hydraulic Systems DigitalizationEnrique BusquetsEngineering Manager – Mobile Systems and Electronics

DC-MH/ENG5-NA | 29/05/2019

© Bosch Rexroth AG 2019. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights.

Hydraulic Systems DigitalizationUnleashing Hydraulics Through Electronics

2

Hydraulic Systems

Digitalization

Hydraulics

Controls

Model-based

engineering

Robotics

Connectivity

& Services

Sensors & HMI

Computer Vision

Artificial

Intelligence

Rexroth

Bosch

DC-MH/ENG5-NA | 29/05/2019


T

ABa1 b1

P

T pST

Hydraulic

Joystick

4TH6

Hydraulic Pilot Control (Non-EH System) Electro-Hydraulic Pilot Control (EH System)

vs.

Hydraulic Systems DigitalizationUnleashing Hydraulics Through Electronics

3

Driver demand is given by hydraulic pilot pressure

No electronics, no software

Driver demand is given by electronic joystick

Software computes the actuation currents for DREs

T

AB

DRE a1 DRE b1P

CAN

Joystick

THE5

ECU

RC28-14/30CAN

Driver demand can be manipulated by softwareNo possibility to manipulate driver demand

DC-MH/ENG5-NA | 29/05/2019


Traditional Load Sensing HydraulicsWorking Principle

4

Pump operates in a closed-loop control with reference on the highest load pressure

dp

1 2

consumer

psys

pLS

pre

ssure

consumer 1

consumer 2

pLS

psys

LS valve stack

A fixed setting of the pump’s control parameters must be a

compromise across all operating conditions

This load pressure generally exhibits large changes

Additional uncertainties exist in the system (i.e. changes in temperature, natural frequencies and damping).

DC-MH/ENG5-NA | 29/05/2019


Traditional Load Sensing HydraulicsWorking Principle

5

In tractor applications, one setting has to cover:

dp

1 2

consumer

psys

pLS

pre

ssure

consumer 1

consumer 2

pLS

psys

LS valve stack

• Multiple different implements

• Varying working conditions & processes

• Individual driver preferences

DC-MH/ENG5-NA | 29/05/2019


Load Sensing Hydraulics

6

consumer 1

consumer 2

pLS

psys

LS valve stackconsumer 1

consumer 2

pLS

psys

LS valve stack

β∩

Architecture Comparison

Electronic Load SensingHydraulic Load Sensing (traditional)

DC-MH/ENG5-NA | 29/05/2019


e-LS Advances Load-Sensing Systems

7

e-LS+++ Efficiency

++ Controllability

++ Oil-flow

+ Operating Modes

+ Machine management

+ Performance

+ Diagnostics

Closed CenterLoad Sensing

++ Efficiency

+ Controllability

+ Oil-flow

+++ Efficiency

++ Controllability

++ Oil-flow

Open CenterLoad Sensing

Open CenterMultiplepumps

+ Oil-flow

+ Energy

Open CenterOne pump

DC-MH/ENG5-NA | 29/05/2019



8

Hydraulic Load Sensing (traditional) Electronic Load Sensing

Pump Pressure Settings Comparison

Not usable

Fixed pressure cut-off

Fixed standby pressure

time

pre

ss

ure Limited pump

pressure range

Maximum allowable pump pressure

Not usable

Minimum needed pump pressure

Variable pressure cut-off

Variable standby pressure

time

pre

ss

ure

Extended pump

pressure range



+ Maximum system pressure is defined by software

+ Possibility of pressure/force limitation for single machine

functions (e.g. gripper force limitation)

+ Lower standby pressure

- No possibility to vary pump settings on demand

DC-MH/ENG5-NA | 29/05/2019



9


Pump Dynamic Behavior Comparison

Not usable

time

pre

ss

ure Fixed pump

dynamic response


Not usable



+ Avoid oscillations

+ Smooth reaction for high controllability

+ Fast reaction for aggressive maneuvers

time

pre

ss

ure

Variable

dynamic response



fastmedium

slow

DC-MH/ENG5-NA | 29/05/2019



10


Pressure Behavior Comparison

Not usable

time

pre

ss

ure

Unfiltered pressure


Not usable



+ Avoid oscillations

+ Smooth reaction for high controllability

+ Fast reaction for aggressive maneuvers

time

pre

ss

ure

Electronic filtering



pump pressure

load pressure

DC-MH/ENG5-NA | 29/05/2019


Electronic Load Sensing (eLS)Various Operation Modes for Different Use Cases

11

oil flow

pre

ss

ure

load pressure

pump pressure

Constant Differential Pressure

dp

variable

pstb

pmax

system(Pressure losses)

oil flow

pre

ss

ure

load pressure

pump pressure

Variable Differential Pressure

dp

variable

pstb

pmax


implement

Energy saving

oil flow

pre

ss

ure

load pressure

pump pressure

Constant Pressure Control

pstb

pmax

control signal

pre

ss

ure

pump pressure

Active Pressure Control

pstb

pmax

e.g.

ctrl sig= alpha drive pedal

Mode 4

Mode 2

Mode 3

Mode 1

DC-MH/ENG5-NA | 29/05/2019



12

oil flow

pre

ss

ure

load pressure

pump pressure


dp

variable

pstb

pmax


oil flow

pre

ss

ure

load pressure

pump pressure


dp

variable

pstb

pmax


implement

Energy saving

oil flow

pre

ss

ure

load pressure

pump pressure


pstb

pmax

control signal

pre

ss

ure

pump pressure


pstb

pmax

e.g.


Mode 4

Mode 2

Mode 3

Mode 1

Enhanced implement performance due to

optimal compensation of pressure losses

Higher stability

Energy saving

DC-MH/ENG5-NA | 29/05/2019



13

oil flow

pre

ss

ure

load pressure

pump pressure


dp

variable

pstb

pmax


oil flow

pre

ss

ure

load pressure

pump pressure


dp

variable

pstb

pmax


implement

Energy saving

oil flow

pre

ss

ure

load pressure

pump pressure


pstb

pmax

control signal

pre

ss

ure

pump pressure


pstb

pmax

e.g.


Mode 4

Mode 2

Mode 3

Mode 1

Fast reaction and increased stability for

certain implements

Working point optimization with adjustable

constant pressure for secondary controlled

implements

DC-MH/ENG5-NA | 29/05/2019



14

oil flow

pre

ss

ure

load pressure

pump pressure


dp

variable

pstb

pmax


oil flow

pre

ss

ure

load pressure

pump pressure


dp

variable

pstb

pmax


implement

Energy saving

oil flow

pre

ss

ure

load pressure

pump pressure


pstb

pmax

control signal

pre

ss

ure

pump pressure


pstb

pmax

e.g.


Mode 4

Mode 2

Mode 3

Mode 1

Possibility of torque based driving

(additional driven axle on trailer, etc.)

Pressure on demand

(front axle activation)

DC-MH/ENG5-NA | 29/05/2019



15

Selecting the Optimized Settings for Each Individual Implement

Manual

Automatic

consumer 1

consumer 2

pLS

psys

LS valve stack

Electronic Load Sensing

β∩

Remote

DC-MH/ENG5-NA | 29/05/2019



16

eLS with Steering

STEERING

consumer 2

pLS

psys

LS valve stack


β∩

***

DC-MH/ENG5-NA | 29/05/2019


Practical Examples

DC-MH/ENG5-NA | 29/05/2019


Electronic Load Sensing (eLS) Hydraulics

18

control signal

pre

ss

ure

pump pressure


pstb

pmax

e.g.


Griper Control

Pressure Too Low Pressure Too HighOptimal and repeatable

pressure setting


(eLS)

Hydraulic Load Sensing

(LS)

DC-MH/ENG5-NA | 29/05/2019



19

oil flow

pre

ss

ure

load pressure

pump pressure


dp

variable

pstb

pmax


implement

Energy saving

Electronic Load Sensing (eLS)Hydraulic Load Sensing (LS)

DC-MH/ENG5-NA | 29/05/2019



20

time

pre

ss

ure

Variable

dynamic response



fastmedium

slow

Front-loader Lifting Control

Electronic Load Sensing (eLS)

DC-MH/ENG5-NA | 29/05/2019



21

time

pre

ss

ure

Electronic filtering



Fan Control

Electronic Load Sensing (eLS)Hydraulic Load Sensing (LS)

DC-MH/ENG5-NA | 29/05/2019


Electronic Load Sensing (eLS)

22

Enhanced Benefits for Most Efficient Working Results

Improved Efficiency due to optimized differential pressure

Increased power and improved response of the implement,

due to variable pressure limits

Individual system adaption

Easy to use with predefined modes

High flexibility, software-based variant handling

Less installation space

Connectivity option for system monitoring

Saves

energy

Ease

of use

Increased

power

Highly

flexible

More

precise

Saves

time

Adaptive

Less

space

DC-MH/ENG5-NA | 29/05/2019


Thank You!Enrique Busquets

[email protected]

engineering manager mobile systems and electronics busquets.pdfdc-mh/eng5-na | 29/05/2019 © bosch...

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