H-Point Measurement Methodology & Techniques: HPM and HPD

Advanced Structures India Pvt Ltd is an independent automotive product development company based out of Bangalore, India with operations in India, China and US. Below is blog entry from our engineers about H-Point Measurement Methods. We can be contacted on business@advancedstructures.in for business enquiries and careers@advancedstructures.in for open positions.


Vehicle development starts with inputs from many domains such as designing, manufacturing, marketing, ergonomics, electronics, etc. Market researchers study the market of a particular country and then focus on the target population for which the vehicle must be developed. Once the target population is identified, the next step is to set the percentile of population for which the vehicle needs to be designed. This is done by the anthropometric survey of the target population. Subject majority (~greater than 80%) decides the actual percentile population for which the vehicle must be produced. This data provides the critical input to set a single point around which vehicle ergonomics and interiors are designed for further vehicle development.

This key point is used at two vehicle development stages –

  • To design the complete interiors, to decide the occupants interior packaging and to understand overall occupant shell which assist in the external design of the vehicle.
  • Auditing or benchmarking of any produced/ competitor vehicle, as this is the key point from where other dimensions can be measured or checked as per requirement.

All vehicles have unique interior packaging & spacing which makes them different from one another in terms of comfort & accessibility. Designing for these parameters starts from the reference point known as “Hip Point”, popularly known as “H-Point”.

H-Point: Understanding and Explanation

H-Point is a pivot point or centre point between the torso line & upper leg line of a human body and is used to specify the occupant’s hip location.

H Point location side view
          H Point location on human body

A non-adjustable seat has only one H-point location, whereas an adjustable seat (e.g., the driver’s) has a number of H-point locations. The extremes of these can be mapped and described as the seat movement envelope for H-Point. In order to have one point of reference for occupant packaging, the manufacturer will select a unique design H-point known as the Seating Reference Point (SgRP or R-Point), which forms reference for all other design needs.

Ergonomics Parameters affected by H Point

 

H-Point Location on a Seat or Vehicle

H-point is measured with respect to a defined set of procedures as specified by the SAE body. The standards followed are SAE J4002, SAE J4003, SAE J4004 & AIS 097 and the measurement of H-Point is termed as “H-point Measurement”. Many other key dimensions & points are also identified during the H-point measurement process. Following are the key measurement techniques:

How to measure H Point

H-Point Machine is a manikin having different percentile adjustments. The construction & various specifications of the manikin are specified in the SAE standards. H-Point machine gives us freedom to physically locate the H-Point location for any specified seat.

The first H-Point machine was HPM-I as defined in SAE J826 standard. HPM-I had some challenges while measuring the H-Point & other key points, hence for the ease of measurement a modified H-point machine was suggested by the SAE body named HPM-II as described in SAE J4002 standard. This resulted in greater ease of use, additional features & measurement capabilities. 

H-Point Design(HPD) tool is a simplified CAD representation of the H-Point Machine. This can be used in any CAD software in association with the physical H-Point Machine for vehicle designing, auditing & benchmarking purposes. SgRP is used to position the HPD in CAD environment.

Both the H-Point Machine & HPD can be used together as well as independently with some prior parameter information for various customer requirements.

Basic differences between HPM & HPD

HPM Vs HPD Comparison for cost, usage,pre-requirements and time.

Difference between HPM and HPD H Point Machine

Utlization of HPM

use of H Point for vehicle development

The use of HPM/HPD during vehicle designing & auditing are mostly done by the manufacturers for the vehicle development. 

Use of H-point Measurement in New Product Development(NPD)

H Point reverse engineering for new vehicle

Since all the vehicles have distinctive dimensions, vehicle benchmarking becomes a very important tool for comparing different competitor vehicles. H-Point plays a major role in benchmarking as it gives a single point of reference for all vehicles. From H-Point we can measure different internal & external dimensions to compare different vehicles on dimensions, ergonomics, interior space availability, etc.

Dimensional measurement using H-point gives various important comparison parameters for vehicles, such as-

  • Comfort which is felt & experienced while using different vehicles in terms of space provided inside a vehicle.
  • Ease of accessibility which a person gets while using internal controls inside a vehicle.
  • Ease with which different percentile population can drive a particular vehicle.

HPM Role in User Comfort Measurement

H-point Measurement also plays a very important & key role in comparing the seat comfort of competitor vehicles for different category & class of vehicles. A seat can be easily benchmarked for a range of percentile population depending upon various features provided in the seat, such as seat travel, height adjustment, lumbar support, etc. Many important vehicle dimensions (more than 100) are listed in SAE j1100 standard which can be obtained from the H-Point location. All these dimensions, from the H-Point location to specified interior & exterior points, helps to benchmark various vehicles with same point of reference.

H Point Machine on Indian car
HPM on vehicle seat

Below are few important HPM outputs

Output of H Point Measurement Process

H Point

It effects all other major internal & external dimensions. Higher H-Point generally provides more legroom for both driver & passenger seats. Buses, SUVs, Minivans, etc type of vehicles have generally higher H-Points. Sedans have generally lower H Point for comfortable riding posture.

Seat Height

Represented as H30 as per SAE J1100. Defines driver’s seated posture. Sports cars & sedans have generally low H30 (about 150-250mm) whereas heavy commercial trucks have high H30(more than 405mm). Adjustable seats provide a better occupancy for larger range of occupants.

H Point Travel

Seat travel decides the adaptability of the seat for a range of population. More seat travel is always preferred as it can accommodate more percentile users & also provides much room for any occupant. This also defines the seat track length. As per SAE, a seat track length of more than 240mm is sufficient to accommodate 95% of drivers in passenger cars. 

Head Room

This is the space provided for sufficient movement of the upper body & head region of the occupant.

Leg Room

Higher the legroom more is the comfort in the occupant area. Hence, sufficient legroom must be provided for a comfortable driving posture. Sedans generally have higher legroom for long & comfortable driving conditions. 

Seat Cushion Angle

A cushion angle of about 5 to 25 degrees is preferred. This permits the user to take best comfortable position by transferring the torso weight on to the seatback. In passenger & sports cars, seatback angle will be more reclined i.e. about 20 to 28 degrees, whereas in heavy commercial vehicles the driver sits more erect with a preferred seatback angle of 12 to 18 degrees.

Lumbar Support

It is one of the most important characteristics of the seat as it defines the shape of occupant’s spinal column in the lumbar area of the seat. The lumbar area must maintain the natural curvature of the spinal column for avoiding any back problems. An adjustable lumbar support will always be helpful for accommodating the seat by more occupants maintaining their natural curvature.

Accelerator Heal Point(AHP)

It specifies the position of the heel of the driver on the depressed floor covering. It is a very important point from design point of view as it defines the seat height.

Challenges of H-point Measurements 

  • Accuracy – As all points are located in open space inside vehicle, it is important to have good accuracy for 3D measurement. We use highly precise CMM instruments having high accuracy (0.01 microns) to get accurate measured values. This removes chance of any error due to manual measurement.
  • Setting up of H-Point Tool – Physically setting up H-Point manikin over the vehicle seat requires high precision. The manikin must be set up strictly following the AIS & SAE standards. We utilise our experience of using H-Point Manikin on Indian as well as international vehicles (for different percentile population) to compare vehicles, with accurate and precise measurements.
  • Time – Setting up H-Point tool is time consuming as it requires strict adherence to process as per standards. Manually measuring is again a tedious work and thus at ASI, we use CMM for taking accurate, easy & rapid measurement once the manikin is set. CAD output data from CMM is further helpful in obtaining other vehicle dimensions which can directly be used in complete vehicle CAD model.

Ashish Kumar

Our Case Studies in Value Engineering – Leveraging Technology, Software and Data

Advanced Structures India Pvt Ltd is an independent automotive product development company based out of Bangalore, India with operations in India, China and US. Below is blog entry from our engineers about how data and technology assets can be leveraged to delivery exceptional outcomes in value engineering activities . We can be contacted on business@advancedstructures.in for business enquiries & careers@advancedstructures.in for open positions.


At ASI we believe in persistence that leads to walk an extra mile to find the best solutions for our customers with minimum resources & available information in limited time. The best of our efforts can be explained through 2 of our recent success stories with our most recent & valuable clients.

As numbers speak for themselves, refer the flow chart below that showcase the outstanding results posted for the two clients and how we offered our smart services to them.

Should Costing Value Engineering Procedure

The value of a product is defined as the ratio of function to cost. Improving function or reducing cost keeping the other factor constant, increases the overall value of the product. There are 3 key stages of value enhancement process explained below:

Stage 1: Client Support

Right information is the key to value engineering, we aim to seek information from the key business verticals (Engineering, Costing, Supply Chain & Marketing) of our client.

Engineering

Engineering team connects us with the product or the services that the client offers to its customers. The communication is through 3D- CAD data, 2D drawings, reports, standards & concept/Idea sheets (including the rejected ones).

Costing

Costing department provides information on all direct & indirect expenses that goes into the making of the product or offering the services. This cost data is aligned with the part specifications such as manufacturing process, material, size etc. The cost database is used in the cost model to analyse the product specific spends & scope of improvements.

Supply Chain

The supply chain connects us with the supplier base and related information. Based on our past experiences with a few customers, it is observed that, supply chain if not managed well can account for maximum scope of optimization. Also, it has been found that the client misses out on the optimization part due to project deadline constraints.

For instance, with one of our clients we could reduce the cost of overall product by 5% only by focusing on packaging efficiency & transportation. (Refer the snapshot below for details)

Value Engineering FIG-2

Marketing

In order to understand the usability of all the features and attributes of a product or a service by the customers, representative from marketing department helps us connect with the consumers of product or the services offered by the client. The key data is obtained by doing surveys & clinics with a sample set of 15-20 customers. This activity suggests what to add or subtract from the product or the services.

In one instance, we have found that the client offered features in the product for some specific purpose that was used only by 20% of the total customer base. However, the cost of adding that particular feature to the product cost a huge sum that was not justified. We helped the client work on developing a variant of that product which incurred only the variable cost. This resulted in increased profit margin on 80 % of products sold without that feature to its customers.

Stage 2: Data Handling

Data Gleaning

In order to garner information/data in an effective manner, ASI’s software team develops smart tools that can collect maximum information in short time. These tools are flexible and custom made as per project requirements.

For instance, we digitized more than 35000 drawings (in the form of CAD or PDF’s) to fetch 45 key specifications per part in just 40 days for one customer. For another customer as a part of value engineering, we scanned through more than 3000 parts and derived specifications w.r.t operator ergonomics, assembly locus & design philosophy.

Data Scrubbing & Shortlisting

Information is useful only when it is correct, so the first thing after receiving data is to chop off the irrelevant or incorrect information.

We believe in 80-20 principle and to find out the most impacting 20% parts, parametric equations called ‘Logic Filters’ are devised. The parameters for these logic filters are selected from 30-40 key specifications like manufacturing method, material, coating/plating & weight etc. derived from the information obtained in stage 1.

 Eventually, these equations result in narrowing down the information to improve focus and possibility of maximum savings through Value Engineering. For instance, the below 2 examples showcase the subtle way of data shortlisting.

The graph A shows the variation in the ratio (Product Cost/Kg of RM) for a set of 80 parts made from same material.

Product Cost in Raw Material per KG

The graph B shows the variation in the ratio (Surface Coating/Unit Area) for a set of 80 parts with similar plating specifications.

Surface Costing Costing

The parts which are not following the trend (a small percentage) can be identified from the above 2 graphs & shortlisted for next stage i.e. Value Engineering & Value Analysis.

Similarly, all relevant parameters for the obtained data during stage 1 can be studied and logical equations can be formed to identify and select the outliers/odd ones.

Stage 3: Value Engineering

Value Drivers Identification

The data collected from marketing is utilized in ascertaining the attributes and features in the product that is in demand at maximum & minimum. The maximum demanded attributes should be projected more towards the customer and the minimum or the unused features should be removed/reduced. The values for which the customer is willing to pay is the critical ones and everything else is irrelevant.

For instance, the table below represents the product features of a kit with its respective value rating. Final rating values are mean of survey data collected from 50 users (Top Management). As we can see, the users gave much preference to AIS compliance, Fuel economy, Serviceability and durability. Other features like weight, accessibility and cost are considered secondary. The survey also revealed that the users are least concerned about aesthetics. This helped in reducing the heavy unnecessary cost that went into painting the kit for aesthetics.

Sample Size: 50 Users (Top Management)

Ranking for Value Engineering

Teardown

By teardown we mean analysis in detail, be it a process, technique, product or the ideas. Generally, teardown is necessary to understand the offerings of other competitors that are selling their products with what features, what quality and at what cost. But, that’s not where the activity ends, we have to see beyond what is obvious and visible that includes capturing the design philosophy of the competitor.

For an OEM, we benchmarked its product with several competitor products. All the competitor products were torn down to last level and other than a few obvious observations, it was found that one of the OEM’s had a modular design philosophy. That particular OEM had various products from different segments which utilized the same set of modules to manufacture them.

 We suggested a similar methodology to our client which resulted in success with numbers as shown below.

Modular Vehicle Architecture

We have a well-setup lab with bays that can disassemble multiple vehicles in parallel without compromising information security.

At our Tear Down lab, we offer:

  1. Disassembling products up-to its last level.
  2. BOM creation with easy part numbering and assembly level identification
  3. Features Mapping (Assembly & Part Level)
  4. Assembly locus/sequence study
  5. Key Specifications mapping (Material, Weight, Size, Coating etc.)
  6. Tools utilization (Type, quantity, usability etc.)
  7. Part/Tool/Feature commonisation study.

For more please click here.

Tear Down and Value Engineering Automotive

Outcomes, Feasibility Study & Implementation

Once all the data is analysed and proposed methods or ideas are compiled, we run the feasibility study within the relevant departments of the client. Later an implementation plan is orchestrated considering the priority that is decided based on the business requirements of the client.

Pratik Kumar Shukla